The utilisation of Immunohistochemistry in breast pathology

1. NAMRATHA
RAVISHANKAR
IMMUNOHISTOCHEMISTRY IN
BREAST PATHOLOGY

4. 1. Analysis of prognostic markers e.g. Prognostic
or Predictive Factors in Breast Carcinoma:
Hormone Receptors
2. Solving common diagnostic dilemmas-
Differential Diagnosis of Epithelial Lesions:
Myoepithelial Cells and papillary lesions of
breast
3. Tumour typing and confirming diagnoses- e.g.
Lobular v Ductal; Luminal v Basal/Myoepithelial;
Distinction DIN (DCIS) and LIN (LCIS)
4. Cell Population in Intraductal Proliferative
Lesions: Homogeneous Versus Heterogeneous
Cell Population (Neoplasia Versus Hyperplasia)

5.  Subtle foci of invasion/Microinvasive
Carcinoma
and status of margins
 Lymph node metastases- Micrometastatic
Disease in Axillary Lymph Nodes (Including
Sentinel Nodes)
 Demonstrating epithelial cells in necrotic
material
 Paget’s Disease
 Systemic Metastasis of Breast Carcinoma
 Metastases to breast
 Spindle cell lesions
 Other markers

6.  Endocrine treatment for breast cancer- late
1890s by Beatson, when he observed what would
now be called responses in a few young women
with apparent locally advanced breast cancer
after he performed surgical oophorectomy.
 Beatson presumed that he was interrupting
neural connections between the ovaries and the
breast, although he was actually removing the
ligand estrogen from the patient’s circulation,
which diminished estrogen availability to its
protein receptor (ER).

7. ER and PR in Carcinoma
breast
 Normal breast epithelial cells- ER and PR receptors ,
proliferate under their influence.
 75% to 85% Ca breast stimulated to grow when these
hormones are present.
ER
 Clinical rationale: identify patients who may benefit from
hormonal therapy. –Stong predictive factor
 It is also a minor prognostic factor.
PR
 PR status is determined to identify a small number of
carcinomas (in most series <5%) that are PgR positive
and ER negative but which may respond to hormonal
therapy. – Predictive factor
 Progesterone receptor is also a minor prognostic
factor

8. Hormone receptors breast cancer (ER) as a
prognostic and predictive factor
 Prognostic factor - any measurement available at
the time of diagnosis or surgery that is associated
with clinical outcome in the absence of systemic
adjuvant therapy.
 Predictive factor - associated with response or lack
of response to a particular therapy.
 ER- Strong predictive factor for response to
endocrine therapy.
 Weak prognostic factor
 PR expression is induced by ER, - surrogate marker
for ER activity
 Additional predictive factor for hormonal therapy
in breast cancer.

9. Estrogen receptors (ER)
● ER-alpha: “classic”
functions of ER;
susceptible to
proliferative stimulation
of estrogen; breast and
endometrium;
● ER-
beta:“housekeeping”
functions; normal
ovary and granulosa
cells, carcinoma of
breast, colon, prostate;
Values differ from ER-
alpha in BRCA1

10. ER
ER status is strongly influenced by tumor grade
and histology
 Virtually all grade I tumors are ER positive, bcl2+
tumors, as are pure tubular, colloid, and classic
lobular carcinoma.
Nadji M, Gomez-Fernandez C, Ganjei-Azar P, et al.
Immunohistochemistry of estrogen and progesterone receptors
reconsidered: experience with 5,993 breast cancers. Am J Clin
Pathol 2005;123:21–27.Oestrogen receptor-
negative breast
carcinoma with a
high concentration
of microvessels
stained with anti-
CD34

11.  PR is an estrogen-regulated gene, and its
synthesis in normal and cancer cells requires
estrogen and ER.
 Some studies have shown that ER and PR status
can change over the natural history of the
disease or during treatment
 Nuclear staining for PR more heterogeneous
than ER - cause of false-negative resultsPR cytoplasmic and
membranous staining is
considered negative

12. ER-positive/PR-negative breast
tumors
 Nonfunctional and unable to stimulate PR
production and that the tumor is, therefore, no
longer dependent on estrogen for growth and
survival.
 Low circulating levels of endogenous
estrogens in postmenopausal women
 Hypermethylation of PR promoter
 Growth factor down regulator of PR
 Brief treatment of patients with ER-positive/PR-
negative tumors with estrogen can restore PR
levels in some of the patients.

13. Recommendations
 ER, PgR, and HER2 determined on all invasive
carcinomas.
 The largest Invasive carcinoma should always
be tested and the results reported in the case
summary.
 If invasive carcinomas - different histologic type
or of higher grade, performing the studies on
these cancers as well is recommended
 If immunohistochemistry for ER and PR is
negative in a core biopsy, it should be
repeated on the excisional breast specimen.

14. FALSE NEGATIVE
 Exposure of the carcinoma to heat ( cautery during
surgery).
 Prolonged cold ischemic time (the time between
tissue removal at surgery and initiation of fixation).
 Type of fixative: ER is degraded in acidic fixatives
such as Bouin’s and B-5.
 Prolonged fixation in formalin: Optimally at least 8
hours in buffered formalin.
 Fixation for more than 3 weeks can diminish
immunoreactivity
 Decalcification: results in loss of immunoreactivity.
 Incorrect antigen retrieval method.
 Non-optimized antigen retrieval.

16. Quantification systems
 Quantification systems may use only the
proportion of positive cells or may include the
intensity of immunoreactivity
 Number of positive cells: As a percentage or
within discrete categories
 Intensity: Refers to degree of nuclear positivity
(ie, pale to dark). The intensity can be affected
by the amount of protein present, as well as
the antibody used and the antigen retrieval
system.
 Most cancers - Heterogeneous immunoreactivity
with pale to darkly positive cells present

17. Scoring for ER Immunostains
 Conventional scoring: Semi quantitative
fashion incorporating both the intensity and the
distribution of specific staining as described by
Mc Carthy, Jr et al.
 Allred scoring: Semi quantitative systemthat
takes into consideration the proportion of
positive cells(scored on a scale of 0-5) and
staining intensity (scored on a scale of 0-3).
 The proportion and intensity were then
summed to produce total scores of 0 or 2
through 8.

18.  Sensitivity of Allred method = 99.4%
 Specificity of Allred method = 99.5%
 Sensitivity of conventional score= 88 %
 Specificity of conventional score= 84%.
Allred scoring for ER reporting and it's impact in clearly distinguishing
ER negative from ER positive breast cancers
Asim Qureshi, Shahid Pervez Department of Pathology, Shaukat
Khanum Cancer Hospital, Lahore,1 Department of Histopathology,
Aga Khan University Hospital, Karachi.2

22. Shousha S
Oestrogen receptor status of breast carcinoma: Allred/H score conversion
table. Histopathology 2008;53(3):346-347

23. HER2 Testing by
Immunohistochemistry
 Scientific rationale: A subset of breast
carcinomas (approximately 15% to 25%)
overexpress the epidermal growth factor receptor
HER2.
 The mechanism of overexpression - amplification
of the gene resulting in increased amounts of
protein
 Clinical rationale: To determine if a carcinoma
will respond to treatment directed against the
protein (eg, treatment with trastuzumab or
lapatinib

26. BRCA 1 mutation
 IHC - new and powerful predictor of BRCA1
mutation status
 ER-negative will roughly double the
probability that the individual is a BRCA1
carrier,
 Er positive - reduce the probability by
approximately fivefold.
The Pathology of Familial Breast Cancer: Predictive Value of Immunohistochemical
Markers Estrogen Receptor, Progesterone Receptor, HER-2, and p53 in Patients
With Mutations in BRCA1 and BRCA2
By Sunil R. Lakhani, Marc J. van de Vijver, Jocelyne Jacquemier, Thomas J.
Anderson, Peter P. Osin, Lesley McGuffog, and Douglas F. Easton for the Breast
Cancer Linkage Consortium
Journal of Clinical Oncology, Vol 20, No 9 (May 1), 2002: pp 2310-2318

27. Standardization for HR testing
 Prompt fixation of breast tissue- 8 to 72 hours of
10% neutral buffered formalin fixation
 Processing by conventional (not microwave
enhanced) tissue processors.
 Formalin newly replenished in the processor
 Processor fluids should not exceed 37°C.
 In vitro diagnostic kits should be used that utilize one
of these ER clones: 6F11, 1D5 or SP1.
 Positive and negative controls, internal and external,
should be used on each run.
 A positive cut-off of 1% - nuclear expression, and
results should be semiquantitated with the percentage
of cells staining and their intensity.

30. Preanalytical
 optimum formalin exposure time for ER determination
is 8 hours
 antigen can be retrieved with increasing retrieval times for
over-exposed tissue, but an under-fixed tissue is
completely useless for biomarker study.
Analytical
 All commercially available antibodies for ER assessment in
breast carcinoma target only ER-alpha isoform.
Post analytical
 NIH Consensus Conference of December 2000 states,
“Any nuclear expression of HRs should be regarded as
a positive result and render a patient eligible for
hormonal therapy

31. Other Prognostic Assays
 Ki-67 (MIB-1)
 Proliferation marker, stains cells in all cell cycle
phases except the resting phase (G0); the
percentage of stained nuclei is the
proliferation index.
 A low proliferation index is associated with slower
tumor growth,better prognosis, whereas the
converse is true for a high proliferation index.

32.  Myoepithelial cells -
easily identified in
normal breast
ductules and acini
 Distinguished from
luminal epithelial cells
by the presence of
smooth muscle fibres.
 Structures dilate and
fill with intraluminal
proliferating cells or
are compressed-
difficult to recognize
the attenuated
myoepithelial cells.

33. p63
 The nuclear protein p63 - homologue of p53
that is expressed in the basal epithelia of
multiple organs.
 In the breast, p63 is positive in nearly 100% of
normal MECs and those associated with benign
proliferations
Advantages
(1) Nuclear staining pattern, which removes the
interpretation difficulties that may be associated
with the cross-reactivity for myofibroblasts seen
with many of the other markers
(2) High sensitivity.

34.  Discontinuous
staining pattern, -
morphologic impression
that MECs are absent
 Positivity in tumor cells,
- 15.7% to 23% of
invasive ductal
carcinomas,85% to
100% of adenoid
cystic carcinomas,
and the majority of
metaplastic
carcinomas
 Potential for a temporal
reduction in its
expression within
archival material

35. SMA
 Normal MEC in 88% to 100% of cases, normal
luminal/epithelial cells in 37% of cases
 Myofibroblasts, and vascular smooth muscle and
pericytes,
 10%–16.1% of invasive ductal carcinomas, scattered
epithelial cells in UDH
Muscle-Specific Actin
 also known as HHF-35 is comparable to SMA in its
sensitivity for
significantly lower specificity.
 In addition to the SMA-like patterns of cross-reactivity
with stromal myofibroblasts, luminal/epithelial cells,
and vessels

36. Smooth Muscle Myosin Heavy
Chain
 SMMHC is a structural component of myosin -
specific for smooth muscle cells, terminal smooth
muscle differentiation.
 100% of the MECs associated with normal breast
ductules and benign breast proliferations, as well
as vascular smooth muscle.
 As compared with SMA and MSA, SMMHC is
significantly easier to interpret
 8% of cases displayed significant
crossreactivity with myofibroblasts

38. CD 10 and Calponin
 CD10 Stains stromal
myofibroblasts - lesser
intensity than is seen with MSA
or SMA, and does not stain
vessels.,
 Values change post-
chemotherapy
 Calponin - Contractile element
expressed in differentiated
smooth muscle cells.
 Highly sensitive for MECs.
 normal breast MECs, vascular
smooth muscle
 Collagenous spherulosis
(CD10+, HHF35+) from

39. Basal-Type and High-Molecular-
Weight Cytokeratins-
 CK 1, CK5, CK5/6, CK10, CK14, and CK17,
react variably with breast MECs.
 The sensitivities of CK5/6, CK14, and CK17 for
MECs- comparable to those of SMA, MSA, p63,
and SMMHC, whereas 34bE12 (which recognizes
CK1, CK5, CK10, and CK14) exhibits
considerably lower sensitivity.
 32% of high-grade DCIS and 38% of invasive
carcinomas - positive for at least one basal-type
and high-molecularweight cytokeratin.

43. Detecting Absence
 Detecting the absence – more problematic than
detecting its presence.
 When IHC fail to reveal myoepithelial cells around
tumor- the diagnosis of stromal invasion is
supported.
 Truly absent or whether they are merely markedly
attenuated and out of the plane of section.
 Reassuring features - Medium to large tumor nests
without detectable myoepithelial cells, multiple
tumor nests without detectable myoepithelial
cells, and lack of reactivity with two different
myoepithelial markers.

44. Avoidance of Pitfalls
 p63 and SMM-HC complement each other well.
 P63 - sensitive and specific nuclear myoepithelial
marker but staining can be discontinuous
 Cytoplasmic myoepithelial marker, such as
SMMHC or calponin, as well will aid
interpretation.
 If these two stains yield unclear results, the
slightly more sensitive but less specific markers
calponin and SMA can be used..
 Combination of the sensitive marker smooth
muscle actin, and two more specific markers
such as smooth muscle myosin heavy chain
and p63.

45. Recommendations for a
Diagnostic Panel
 The optimal antibody also depends upon the type
of lesion being evaluated.
 Reactive stroma - p63 is an excellent choice
because it does not stain myofibroblasts or
blood vessels.
 p63 is less adroit at highlighting architecture in
small glandular proliferations such as sclerosing
adenosis, and in these cases a cytoplasmic
marker such as SMA may be easier to interpret.

46. MYOEPITHELIAL CELL MARKERS IN THE
EVALUATION
OF BENIGN SCLEROSING LESIONS
 Radial scar and complex sclerosing lesion -
Proliferation of benign glands and tubules within a
fibrous/fibroelastotic stroma.
 MECs associated with sclerosing lesions may
have different
immunophenotypic characteristics from the MEC
layer
 Reduced expression of CK5/6 in 32% of cases,
SMMHC in 20%, CD10 in 15%, p63 in 10%, and
calponin in 6%, compared to that of normal
MECs

50. Adenosis - benign proliferative lesion that usually
occurs as part of the spectrum of proliferative
fibrocystic change
Myoepithel
ial cells
Collagen Other
markers
Tubular
Carcinoma
Invasive tubules
Apical snouts
Desmoplasia
Absent Absent EMA +
ER/PR +
Microgland
ular
adenosis
Round glands
in fat
Flat to cuboidal
cells
Secretions
Absent Present S100+
ER/PR
negative
EMA negative
EGFR +
Tubular
adenosis
Lobulocentric
Tubules
Present Present S100 negative
Sclerosing Lobulocentric Present Present S100 negative

52. Invasive Carcinoma Versus In Situ Carcinoma
DCIS mimicking invasion
 Epihelial tributaries adjacent to DCIS
 Inflammation and sclerosis
 DCIS with sclerosing adenosis and radial scar,
cancerisation of lobules - Invasive appearance
Invasive carcinoma mimicking CIS
Cribriform carcinoma and Adenoid cystic carcinoma
 Myoepithelial cells can become diminished in
number in both in-situ carcinomas(5%)

53. Detection of microinvasion
 Stromal invasion occurs when malignant epithelial
cells extend beyond the myoepithelial cell layer
and
 Earlier investigators- antibodies to basement
membrane components - collagen IV and laminin
to differentiate between in situ and invasive
carcinomas.

54. Irregularly shaped nests of neoplastic cells in a sclerotic
background
SMMHC highlights the myoepithelial cells surrounding
the DCIS within the complex sclerosing lesion. Small foci
of invasive ductal carcinoma - apparent in the
immunostained section

55. MARKER COLLAGENOU
S
SPHERULOSIS
ACC CRIBRIFORM
DCIS
INVASIVE
CRIBRIFORM
CARCINOMA
p63 + at the
periphery and
surrounding
lumens
+ at the
periphery and
the basaloid
cells
+ at periphery
only
Negative
SMMHC + at the
periphery and
surrounding
lumens
Negative + at periphery
only
Negative
CALPONIN + at the
periphery and
surrounding
lumens
Negative + at periphery
only
Negative
C- KIT Negative Positive
tumour cells
Negative Negative
MYOEPITHELIAL CELL MARKERS IN THE
EVALUATION
OF CRIBRIFORM LESIONS OF THE BREAST

56. Special types of carcinomas -
myoepithelial markers
 Adenoid cystic carcinoma, low-grade
adenosquamous carcinoma, malignant
adenomyoepithelioma, and malignant
myoepithelioma
 Metaplastic carcinomas, including spindle cell
carcinomas, may also stain for myoepithelial
markers.
 Myoepithelial markers can stain the periphery of the
invasive adenosquamous tumor nests, simulating
an intact myoepithelial cell layer
Current Practical Applications of Diagnostic Immunohistochemistry in
Breast Pathology
Melinda F. Lerwill, MD
Am J Surg Pathol 2004;28:1076–1091)

57.  Signet ring cell carcinoma- (GCDFP-15 or BRST2),
Estrogen receptor and MUC1 ,CK7 +,and negative
for CK20
 Ca with neuroendocrine differentiation: specific but
quite heterogeneous positive reaction chromogranin
or synaptophysin and NSE
 Secretory carcinoma - alpha-lactalbumin, beta-
casein, and HMFG-2 (all milk proteins), S100 protein
and CEA. ER - negative
 Sebacceous Ca- Pan CK +.PR+, ER-
 Medullary Ca- ER and PR- . HER2/neu –
 Tumor cells - + for HMW-CK and CK19,
basal/myoepithelial markers such as CK5/6, CK14,
p63, and CD10
 Lipid-rich ca - lactoferrin and alpha-lactalbumin.

58.  + for both LMW-CK
(such as CK8/18) and
HMW-CK or basal-
type cytokeratins
(such as CK34BE12,
CK5/6, CK14). .
 SMA,Calponin, and
p63+
 CD117 + .ER,PR, and
HER2/neu are very
often negative in
adenoid cystic
carcinoma
Adenoid cystic carcinoma showing positive
staining with SMA
KIT expression: cribriform pattern
and solid pattern , more than 90% of
cells expressed KIT, with
membranous and/or cytoplasmic+
Benign ductal epithelial
cells expressed KIT whereas
myoepithelial cells did not express

59.  HER2 overexpression
(95%) and p53 (70%).
 MUC1 - unusual
immunoreactivity
limited to the basal
surface of the cells
 Conventional- MUC1-
intracytoplasmic or
apical.
 Reversal of cell
orientation - important
factor in the
morphogenesis and
pathogenesis of
invasive
micropapillary
carcinoma

61.  p63 - highest sensitivity and lowest cross
reactivity, and the nuclear staining is easy to
interpret.
 CK5/6 appears to have a better sensitivity and
specificity than other markers.
 Neuroendocrine markers are useful in
differentiating solid papillary carcinoma (spindle
cell type, neuroendocrine type) from papilloma
with extensive florid epithelial hyperplasia.

63. Residual benign intraductal
papilloma with solid and cribriform
pattern, indicative of DCIS.
p63 – MECs are present within the
papillae of the residual papilloma
are greatly reduced in number in the
portion of the papilloma occupied by
DCIS/atypia

65. Encapsulated papillary carcinoma
Encapsulated papillary carcinoma-
CD10. Myoepithelial cells are not
present either within the papillae or at
the periphery of the nodule (note
myoepithelial cell reactivity of
adjacent normal duct).

66. Solid papillary carcinoma
Endocrine features, immunoreactivity for
chromogranin and synaptophysin.

70. Basal like carcinomas
 Expression signature similar to that of the
basal/myoepithelial cells of the breast
 Transcriptomic characteristics similar to those of
tumors arising in BRCA1 germline mutation
carriers
 High nuclear grade, high mitotic activity,
coexpression of high-molecular-weight
cytokeratins, EGFR and vimentin, and a lack of
expression of ER and PR

71.  Poorer survival if express CK 17 or CK 5/6 CK
5/6 or EGFR , HER2+
 Not all triple negative tumors express basal
cytokeratins, and a subset of basal-like
carcinomas are not triple negative.
 The combination of ER(-) Her2/neu(-) CK5/6(+)
and EGFR(+) has a 76% sensitivity and 100%
specificity

75. TUMOUR TYPING- Definition of Lobular
Differentiation
 Morphology (the traditional method);
 Immunohistochemical (loss of E-cadherin
immunoexpression and mislocalization of p120); or
molecular (mutation in E-cadherin gene 16q22.1).
 Occasional cases with morphologic and molecular
criteria for lobular differentiation - variable
degrees/patterns of Ecadherin expression
 May be valid to equate “loss of E-cadherin staining”
with lobular differentiation,
 Not valid to exclude lobular differentiation in
morphologically “lobular” tumors just because of
positive E-cadherin staining.

76.  Molecular defects in the E-cadherin gene - may still
express E-cadherin , protein may not be functional in
terms of achieving cell to cell adhesion (Da Silva et al.
Am J Surg Pathol 2008; 32: 773),
 Granular cytoplasmic pattern, dot-like or patchy
discontinuous membranous pattern or even
continuous membranous pattern
 “aberrant Ecadherin reactivity” should not
automatically exclude a diagnosis of lobular
differentiation
 Not automatically equated with ductal
differentiation
 Complete lack of E-cadherin: Supports a
diagnosis of lobular differentiation.
 Presence of E-cadherin: Does not exclude lobular
differentiation. Revert to morphology and/or p120

79.  E-CD is a calcium-dependent, epithelial-specific
cell-cell adhesion molecule whose reduced or
lost expression is associated with tumor
dedifferentiation and increased metastatic
potential in human carcinomas.
 Membrane staining in luminal cells and granular
in myoepithelial cells
 extended spread of lobular carcinoma in situ and
the peculiar diffuse invasion mode of invasive
lobular carcinoma.

81. p120 catenin (a.k.a. p120):
 Inner membrane bound protein associated
with E-cadherin.
 In ductal epithelium (benign or malignant),
p120 - membranous expression.
 In lobular cancer, loss of E-cadherin is
associated with loss of the anchoring of p120
to the membrane
 Cytoplasmic expression
 Helpful adjunct to E-cadherin- in the setting of
aberrant E-cadherin reactivity
 Membranous p120: Ductal differentiation.
 Cytoplasmic p120: Lobular differentiation.

83. Mammary intraepithelial neoplasia, NOS type:
Both E-cadherin and CK34BE12 negative: negative
hybrid lesion.
Both E-cadherin and CK34BE12 positive: positive
hybrid lesion.

85. UDH VERSUS ADH/DUCTAL
CARCINOMA IN SITU
 Normal breast glands and ducts are composed of
3 cell types : luminal, basal, and myoepithelial.
 The luminal cell types express LMW cytokeratins
(CKs)
 Myoepithelial cells express basal cell–type CKs-
HMW CKs
 Thee HMW-CKs are CK34BE12(CKs 1, 5, 10,
and 14), and monoclonal HMW-CKs such as
CK5/6 or CK14.

86. Luminal epithelial cells and
myoepithelial (or basal) cells
 UDH - Heterogeneous cell population -
epithelial and modified myoepithelial cells
(divergent cell population).
 Both low (CK8, CK18, CK19) and high molecular
weight cytokeratins (HMW-CK), such as CK5/6,
CK14, and CK34betaE12
 ADH/LG-DCIS- clonal derivation- Markers of
only 1 cell type, usually luminal (CK8, CK18,
CK19)
 Small percentage show basal cell
differentiation, a phenotype more typical of
high-grade DCIS
 Note that CK5/6 is more specific than CK34BE12

87. Current Practical Applications of
Diagnostic Immunohistochemistry in
Breast Pathology
Melinda F. Lerwill, MD
Am J Surg Pathol 2004;28:1076–1091)

89. UDH, keratin 903, note strong cytoplasmic staining of cells , ADH, keratin 903,
note minimal to no staining of cells

91.  The loss of TGF-β2 expression in UDH has
been suggested as a predictive factor for the
development of invasive breast cancer in the
future
 TGF-α which showed an increasing staining
intensity in malignant tumors

92. CHARACTERIZATON OF
METASTATIC
ADENOCARCINOMAS
 The breast itself is an uncommon site of metastatic
disease.
 Cutaneous melanoma is the most common
extramammary solid malignancy to metastasize to
the breast.
 Pulmonary, ovarian, gastric, and renal carcinomas
are also common sources of metastases to the
breast, as is prostatic carcinoma in males
 In 24% to 40% of cases the breast lesion is the first
presentation of an occult malignancy.
 Absence of an in situ component in a tumor that
is negative for ER, PR, and HER2/neu is a ‘‘red-
flag’

93.  Ovary- WT-1 antibody together with a negative
reaction for GCDFP-15 and/or mammaglobin,
provides strong evidence for metastases.
 Negativity for pan-CK, coupled with
immunoreactivity to HMB-45 and Melan-A, is
consistent with metastatic melanoma.
 Positivity for S100 protein alone is of limited value -
Benign and malignant breast epithelium.
 Metastasis from a gastric signet ring cell carcinoma vs
invasive lobular carcinoma - IHC panel of ER, PR,
and CDX-2 (caudalrelated homeobox gene 2)
antibodies is helpful.

94. METASTATIC CARCINOMA,
UNKNOWN
PRIMARY ORIGIN

96. Breast Versus Lung
 Solitary lung lesions in patients with a history of
breast cancer and in the workup of metastases of
unknown primary.
 GCDFP-15 and TTF-1
Breast Versus Ovary
 Same patient population, particularly in those
women who harbor BRCA mutations.
 GCDFP-15 and sometimes WT-1
 WT-1, being expressed in 96% of ovarian serous
ca and 2% in all breast carcinoma

97. Breast Versus Stomach
 GCDFP-15, ER, and CK20, + for GCDFP-15 is
consistent with a breast primary
 An ER+ signet-ring cell carcinoma is more likely to be
of breast origin, and a CK20+ tumor is more likely to
be of gastric origin.
 A CK20+/ ER+ signet ring cell carcinoma is more
likely to be of breast origin
Breast Versus Melanoma
 Positive reactions for HMB-45 and MART-1, and a
negative reaction
 for cytokeratin
 S-100 is of limited value

98. SENTINEL LYMPH NODE
EVALUATION
 Multiple step levels, cytokeratin immunostains,
and/or molecular diagnostics are all variously
used.
 Increased detection of micrometastases and
isolated tumor cells.
 Although routine IHC staining with cytokeratin is
not - Invasive lobular carcinoma
 Suspicious for, but not diagnostic of, lymph
node metastases on H&E rather than as a
routine method of evaluating nodes in cases
of invasive lobular cancer.

99.  The keratin cocktail AE1/AE3, which stains
predominantly high-molecular-weight
keratins, or a wide-spectrum pan-CK are most
commonly used.
 CAM 5.2 and AE1, which stain only low-
molecular-weight keratins.
 Not all epithelial cells in lymph nodes represent
metastatic carcinoma.
 A biopsy may displace benign breast epithelia,
which then drain to the axillary nodes, so-called
benign transport.

100.  Reticulum cells -+
Cam5.2 or pan-
cytokeratin is used,but
much less so when
AE1/AE3 or AE1
alone is used.
 Plasma cells

101.  Current AJCC staging criteria include a special
identifier “i+” to indicate when metastatic
deposits >0.2 cm are detected only on
immunohistochemical stains.
 Metastases larger than 0.2 cm are considered N1
regardless of the method of detection.

102. Paget’s Disease
Positive
 LMW-CK (CK8, CK18,
CK19)
 CK7,EMA GCDF-15 , CEA,
CD138, p53
 Overexpress HER2/neu
 Negative
 CK20, ER and PR
CK7

103.  Toker cells
 CK 7 +/-
 ER+, PR+, CD138-,
p53-, HER2-, Low Mib-
1
 Melanoma
S100, HMB 45 and Vimentin
Melanin, cytoplasmic mucin
vacuoles.
 Extramammary Paget’s
disease
 HMWCK, p63+
CK 20 and CK 7 positive
MUC1 - only MUC in both
MPD and EMPD.
Paget cells in MPD- about
75%) express MUC3
> 40% of EMPD were
positive for MUC5AC

104. Spindle cell lesions
 Pure spindle cell lesion or only subtle cohesive foci-
IHC for cytokeratins
 Bland spindle cell lesions as spindle cell carcinoma
can resemble fibromatosis.
 Spindle cell carcinomas typically express basal
cytokeratins or myoepithelial markers.
 No marker is expressed by all spindle cell carcinomas
-important to use a panel of antibodies to both basal
and luminal cytokeratins.
 Cytokeratin 14, cytokeratin 5/6, 34βE12 (basal),
CAM5.2, cytokeratin 7 (luminal), MNF116 and
AE1/AE3 (broad spectrum).
 Cytokeratin expression per se in a spindle cell lesion
does not exclude other diagnoses.

106. Panel of IHC often needed to demonstrate tumor cell reactivity
 Antibodies to high molecular weight
cytokeratins most sensitive
 – Pankeratin MNF116
 – 34βE12
 – CK 5/6
 – CK 14
 ER/PR/Her2neu
 Myoepithelial markers- SMA, S100, P63, CD10
and Actin
 Laminin

109. Spindle cell carcinoma that is positive with
CAM5.2 - more cohesive areas (B). There
is nuclear expression of β-catenin by the
carcinoma cells. Note that the endothelial
cells show cytoplasmic staining, but the
nuclei are negative

111.  p63 was consistently negative in the spindle and epithelial
cell components of all benign and malignant Phyllodes
tumors
 The sensitivity and specificity of p63 as a marker for
metaplastic carcinoma is 86.7% and 99.4%, respectively, with
a 100% specificity for MCB with spindle cell and/or
squamous areas.

113. Bcl 2
 Zhang et al. - a) bcl-2 expression - better response to
hormone therapy, and the expression of bcl-2 is a
favorable prognostic factor regardless of nodal status.
 Berardo et al.- high bcl-2 expression was associated
with a significantly improved disease-free survival and
overall survival,
 Gee et al. found that patients with estrogen-receptor
and bcl-2-positive tumors were particular responsive
to endocrine therapies that included an anti-estrogen.
 van Slooten et al. found no association between bcl-
2 expression and response to perioperative
chemotherapy in node-negative patients.
 Bonetti et al. reported a higher response rate to
chemotherapy among tumors classified as bcl-2
positive with immunostaining in ≥40% of tumor cells.

114.  Antibodies to D2-40,
LYVE-1, and other
endothelial markers -
uncertainty about the
presence of
lymphovascular
invasion at a particular
site in the tissue
 VEGF, CD31 and CD34
 Angiogenesis in breast
carcinoma - relevance of
tumor vascularity to
known prognostic
markers and to
prognosis
 UPA1 and PAI 1

115. 1. Prognostic or Predictive Factors in Breast
Carcinoma: Hormone Receptors
2. Differential Diagnosis of Epithelial Lesions:
Myoepithelial Cells (Panel of p63, SMMHC and
SMA and basal cytokeratins)- Sclerosing
lesions, Adenosis and Cribriform lesions
3. Papillary lesions of breast- Myoepithelial
markers
4. Tumour typing and confirming diagnoses-
Lobular v Ductal; (DCIS) vs LIN (LCIS)- E
cadherin,p120 catenin, CK8, CK34 betaE12
5. Homogeneous Versus Heterogeneous Cell
Population (Neoplasia Versus Hyperplasia)-
CK34 betaE12 and CK5/6
ER

116.  Basal like carcinomas- ER, PR(-) Her2/neu(-)
CK5/6(+) and EGFR(+)
 Special types of invasive carcinoma- ACC-
CD117
Micropapillary-MUC1, ER/PR
 Metastatic carcinoma- Unknown primary-
GCDF15, ER,PR, CK7, CK20
 Metastasis to breast- Melanoma markers,
Ovary,
 Sentinel lymph node evaluation- Keratins in
lobular carcinoma

117.  Spindle cell lesions of breast- Metaplastic
carcinoma- – Pankeratin MNF116
 – 34βE12, CK 5/6, CK 14, ER/PR/Her2neu
 Myoepithelial markers- SMA, S100, P63, CD10
and Actin Laminin
 Pagets disease of breast- LMW-CK (CK8,
CK18, CK19)CK7,EMA GCDF-15 , CEA,
CD138, p53 Overexpress HER2/neu

118. THANK YOU