Mamatha Chivukula

Basal phenotype of ductal carcinoma in situ: recognition and immunohistologic profile.

The basal phenotype of breast carcinoma was demonstrated from a study of gene expression profiles, which demonstrated five carcinoma phenotypes with differing immunohistologic profiles and outcomes. The basal phenotype, so-named because of an immunohistologic profile that is similar to myoepithelial cells of the breast, has poor outcomes. While the invasive basal phenotype has been described, there is a paucity of literature regarding the existence or recognition of a precursor lesion. We searched our CoPath database for breast carcinomas in the age group of 37 years or less, and this yielded 98 cases from the years 2001 to April 2006. Pathology reports were screened for those cases that were negative for estrogen and progesterone receptors and HER-2/neu (triple negative). A total of 16 cases (16/98, 16%) fulfilled these criteria. Histology was reviewed and immunostains were performed for Cytokeratins 14, 17, and 5/6, vimentin, EGFR, c-kit, smooth muscle actin and p63. All 16 cases had a high-grade invasive ductal carcinoma, Nottingham score 9/9, with geographic necrosis, good circumscription and lymphoid infiltrates. Of the 16 cases, 13 exhibited at least one area of ductal carcinoma in situ (DCIS). The DCIS types were solid, flat or micropapillary, high nuclear grade, with comedonecrosis and invariably associated with intense lymphoid inflammatory cell infiltration. Of 16 invasive cases, 14 (88%) were positive for CK14, CK17, CK5/6 and EGFR; 94% were vimentin positive, while half or less of cases were positive for smooth muscle actin, c-kit or p63. All of the DCIS components demonstrated the same immunohistologic profile as the invasive component. A DCIS component of solid, flat or micropapillary type exists in the basal phenotype of breast carcinoma, and it demonstrates the same immunophenotype as the invasive carcinoma, typically positive for CK5/6, CK14, CK17, vimentin and EGFR, but negative for ER/PR and HER-2/neu.

Lobular versus ductal breast neoplasms: the diagnostic utility of p120 catenin.

The distinction between lobular and ductal lesions of the breast is important in several circumstances. Diagnostic reproducibility of lobular versus ductal lesions, based on histology alone, is less than optimal. The proper distinction between atypical lobular hyperplasia, lobular carcinoma in situ and low-grade ductal carcinoma in situ is critical for patient management. Patients who have a core biopsy of invasive lobular carcinoma often have preoperative magnetic resonance imaging to prepare the surgeon for proper margin attainment. E-cadherin, a negative membrane marker for lobular neoplasia, is useful in the distinction of lobular versus ductal neoplasia, but as a negative marker, can be difficult to interpret in particularly challenging cases. In this study, we surveyed primary and metastatic ductal lesions (62) and lobular lesions (64) of the breast to determine if P120 catenin is useful in the diagnostic distinction between lobular and ductal neoplasia. Primary breast ductal and lobular preneoplastic and neoplastic lesions were immunostained with E-cadherin and P120ctn and independently classified as ductal or lobular lesions. In addition, a wide array of carcinomas of different types were surveyed with P120ctn in tissue microarrays to ascertain whether the cytoplasmic P120ctn immunostaining pattern observed in lobular neoplasia was unique. Accurate categorization of ductal versus lobular neoplasia in the breast with P120ctn immunostaining was effective in all cases. Separation of low-grade ductal carcinoma in situ from lobular neoplasia was efficient. Diagnostically, P120ctn was particularly useful in identifying early lesions of lobular neoplasia. Of the other tumors that may morphologically mimic lobular carcinoma, only the diffusely infiltrating variants of rectal and gastric carcinomas showed diffuse cytoplasmic P120ctn immunostaining. Caution should be exercised when examining tumors in metastatic sites with P120ctn, with the incorporation of an appropriate panel of immunostains.

CSPG4 Protein as a New Target for the Antibody-Based Immunotherapy of Triple-Negative Breast Cancer

BACKGROUND The cell surface proteoglycan, chondroitin sulfate proteoglycan 4 (CSPG4), is a potential target for monoclonal antibody (mAb)-based immunotherapy for many types of cancer. The lack of effective therapy for triple-negative breast cancer (TNBC) prompted us to examine whether CSPG4 is expressed in TNBC and can be targeted with CSPG4-specific mAb. METHODS CSPG4 protein expression was assessed in 44 primary TNBC lesions, in TNBC cell lines HS578T, MDA-MB-231, MDA-MB-435, and SUM149, and in tumor cells in pleural effusions from 12 metastatic breast cancer patients. The effect of CSPG4-specific mAb 225.28 on growth, adhesion, and migration of TNBC cells was tested in vitro. The ability of mAb 225.28 to induce regression of tumor metastases (n = 7 mice) and to inhibit spontaneous metastasis and tumor recurrence (n = 12 mice per group) was tested in breast cancer models in mice. The mechanisms responsible for the antitumor effect of mAb 225.28 were also investigated in the cell lines and in the mouse models. All statistical tests were two-sided. RESULTS CSPG4 protein was preferentially expressed in 32 of the 44 (72.7%) primary TNBC lesions tested, in TNBC cell lines, and in tumor cells in pleural effusions from 12 metastatic breast cancer patients. CSPG4-specific mAb 225.28 statistically significantly inhibited growth, adhesion, and migration of TNBC cells in vitro. mAb 225.28 induced 73.1% regression of tumor metastasis in a TNBC cell-derived experimental lung metastasis model (mAb 225.28 vs control, mean area of metastatic nodules = 44590.8 vs 165950.8 μm(2); difference of mean = 121360.0 μm(2), 95% confidence interval = 91010.7 to 151709.4 μm(2); P < .001). Additionally, mAb 225.28 statistically significantly reduced spontaneous lung metastases and tumor recurrences in an orthotopic xenograft mouse model. The mechanisms responsible for antitumor effect included increased apoptosis and reduced mitotic activity in tumor cells, decreased blood vessel density in the tumor microenvironment, and reduced activation of signaling pathways involved in cell survival, proliferation and metastasis. CONCLUSIONS This study identified CSPG4 as a new target for TNBC. The antitumor activity of CSPG4-specific mAb was mediated by multiple mechanisms, including the inhibition of signaling pathways crucial for TNBC cell survival, proliferation, and metastasis.

Pleomorphic Lobular Carcinoma In Situ (PLCIS) on Breast Core Needle Biopsies : Clinical Significance and Immunoprofile

Pleomorphic lobular carcinoma in situ (PLCIS) is a more recently characterized entity that mimics high-grade ductal carcinoma in situ (DCIS). PLCIS is sometimes treated similar to high-grade DCIS, but no consensus has been reached for the most appropriate treatment. The aim of this study is to evaluate the histologic and immunohistologic profile of pure PLCIS on core needle biopsies and present follow-up clinical data. We reviewed 12 cases of pure PLCIS diagnosed on core needle biopsies of the breast along with subsequent surgical resections. Histologically, all cases showed dyscohesive cells with grade 3 nuclei, prominent nucleoli, and moderate to abundant eosinophilic cytoplasm. A panel of immunohistochemical stains to study this entity included E-cadherin, P120 catenin, estrogen receptor, progesterone receptors, HER2/neu, and Ki-67 (MIB-1). Residual PLCIS was found on excisional biopsies in 83% (10/12) cases. Invasive lobular carcinoma was found in 25% (3/12) cases. The lobular nature of all cases was confirmed by negative E-cadherin and cytoplasmic-dominant staining with P120 catenin. PLCIS was positive for estrogen receptor in 92% (11/12); progesterone receptor in 50% (6/12), and Her2/neu was positive in 25% (3/12). A moderate to high proliferation activity was observed with MIB (Ki-67) staining in 92% (11/12) cases. We conclude that PLCIS has a lobular immunostaining pattern for P120 catenin and E-cadherin indicating disruption of the E-cadherin/P120 catenin complex. This entity has aggressive parameters similar to high-grade DCIS including grade 3 nuclei, high Ki-67 (MIB-1) index, and HER2/neu positivity. PLCIS has a significant association with other high-risk lesions and invasive lobular carcinoma.

Immunohistochemical comparison of gastrointestinal stromal tumor and solitary fibrous tumor

CONTEXT The differential diagnosis of gastrointestinal stromal tumors (GIST) and solitary fibrous tumors (SFT) may be a diagnostic challenging because of overlapping clinicopathologic features. Many studies have shown consistent immunoreactivity for CD117 (c-Kit) in GIST. However, only a few studies have evaluated CD117 expression in SFT, and these studies have used an antibody from Santa Cruz Biotechnology. In non-GIST lesions, reactivity with this antibody has been shown to differ from that with a CD117 antibody from Dako Corporation. The immunoreactivity of SFT with the Dako CD117 antibody has not been reported. Conversely, CD99 is a marker for SFT, and its expression in GIST has not been evaluated. OBJECTIVE To study the immunohistochemical profiles of GIST and SFT to evaluate their diagnostic overlap. DESIGN We studied the immunoreactivity of 27 unequivocal GIST and 19 unequivocal extra-abdominal SFT for CD117, CD34, CD99, alpha-smooth muscle actin, vimentin, CD31, S100 protein, and muscle-specific actin. All antibodies, including CD117, were from Dako Corporation. RESULTS We found positive immunoreactivity for CD117 in 100% of GIST and none of SFT; for CD34 in 89% of GIST, and 100% of SFT; for CD99 in 89% of GIST and 100% of SFT; for alpha-smooth muscle actin in 48% of GIST and 31% of SFT; for vimentin in 89% of GIST and 90% of SFT; and for muscle-specific actin in 22% of GIST and none of SFT. None of the GIST or SFT showed immunoreactivity for CD31 and S100 protein. CONCLUSIONS The major difference between GIST and SFT was strong CD117 immunoexpression in all GIST and an absence of this expression in all SFT. With the exception of muscle-specific actin, the prevalence of immunoreactivity for the markers studied did not differ substantially between these 2 tumors. We conclude that GIST and SFT show distinctly divergent immunoprofiles with respect to CD117 and muscle-specific actin.

The ductal phenotypic expression of the E-cadherin/catenin complex in tubulolobular carcinoma of the breast: an immunohistochemical and clinicopathologic study.

Tubulolobular carcinoma is a type of mammary carcinoma that displays an admixture of invasive tubules and lobular-like cells. Previous reports have shown it to share clinical similarities to lobular carcinoma, whereas more recent studies have shown it to be E-cadherin positive. The aim of the current study was to further explore the immunophenotype of tubulolobular carcinoma, and to document its natural behavior. Nineteen cases of tubulolobular carcinoma and 10 cases each of tubular and lobular carcinoma were retrieved for comparison analysis. Immunohistochemistry was performed with antibodies against estrogen receptor, progesterone receptor, HER2/neu, 34βE12, E-cadherin, and the catenins. Twenty-five percent of patients with tubulolobular carcinoma presented with greater than stage I disease, compared to 0 and 60% of patients with tubular and lobular carcinoma, respectively. Two patients with tubulolobular carcinoma had tumor recurrence, one of whom also developed metastasis. The majority of all carcinomas were estrogen and progesterone receptor positive. E-cadherin displayed membranous staining in all tubular and tubulolobular carcinomas, and was negative in all lobular carcinomas. Half of each carcinoma subtype displayed granular cytoplasmic 34βE12 immunoreactivity. α-Catenin exhibited partial or complete membranous staining in all tubulolobular and tubular carcinomas, and was negative in all lobular carcinomas. β-Catenin displayed membranous staining in tubulolobular and tubular carcinomas, whereas all lobular carcinomas had coarse cytoplasmic immunoreactivity. p120 and γ-catenin displayed membranous staining in 100% of tubulolobular and tubular carcinomas and cytoplasmic staining in 100% of lobular carcinomas. Tubulolobular carcinoma of the breast is thus a distinct type of mammary carcinoma that displays both tubular and lobular patterns histologically but displays the membranous E-cadherin/catenin complex characteristic of the ductal immunophenotype. Tubulolobular carcinoma appears to be more aggressive than tubular carcinoma, as 16% of patients had lymph node metastases, although all were alive at a mean follow-up of 40 months.

An immunohistochemical panel to differentiate metastatic breast carcinoma to skin from primary sweat gland carcinomas with a review of the literature.

CONTEXT Approximately 25% of patients with breast cancer develop cutaneous metastases. Sweat gland carcinomas (SGCs) account for about 0.05% of all cutaneous neoplasms. Cutaneous metastases of breast carcinoma (CMBCs) (especially the ductal type) can be difficult to distinguish from SGCs. Treatment and prognoses for these 2 types of tumors differ radically, making accurate histologic diagnosis crucial. Although a few studies attempt to differentiate these entities employing immunohistochemical (IHC) studies (some of which we review here), to date, no panel of IHC stains exists, to our knowledge, to distinguish these entities. OBJECTIVE To devise a panel of IHC stains to distinguish CMBC from SGC. DESIGN Twelve cases of ductal CMBCs (11 not otherwise specified type, and 1 basal phenotype), 11 cases of SGCs (5 eccrine carcinomas, 3 porocarcinomas, and 3 microcystic adnexal carcinomas), 2 benign sweat gland neoplasm cases, and 2 primary breast cancer cases were retrieved and analyzed with the following IHC panel: mammaglobin, gross cystic disease fluid protein (GCDFP) 15, p63, basal cytokeratins (CK5, CK14, and CK17), androgen receptor, and PAX5. RESULTS The p63 was only weakly expressed in 1 of 12 CMBC cases (8.3%), whereas it was strongly expressed in 10 of 11 SGC cases (90.9%) (P < .001). Basal cytokeratins demonstrated a similar immunoprofile in the SGC group, with 10 of 11 cases (90.9%) expressing all 3 markers, and a variable immunoprofile in the CMBC group with 0% (CK14) (P < .001) to 16.7% (2 of 12 cases; CK5 and CK17) (P < .001) expression. Mammaglobin was expressed in 8 of 12 cases (66.7%) of CMBC. CONCLUSIONS Together, these 5 IHC stains were combined to make a panel that was 100% sensitive and 91% specific in distinguishing between CMBC and SGC.

Clinicopathologic implications of "flat epithelial atypia" in core needle biopsy specimens of the breast.

Flat epithelial atypia (FEA) is an emerging entity of uncertain clinical significance, and outcome data are sparse. The aim of this study was to evaluate the clinicopathologic significance of this entity for proper management. All core needle biopsy (CNB) specimens diagnosed as atypical ductal hyperplasia (ADH) from January 2006 to April 2008 were retrieved. H&E-stained slides of 5 levels on each case were reviewed. The differences in upstaging in subsequent excisions in the FEA and ADH group (31/189 [16.4%]) vs the pure FEA group (5/35 [14%]) and pure FEA (5/35 [14%]) vs pure ADH (5/45 [11%]) were not statistically significant. We observed that FEA evolved into ADH at the same site at an average of 3 to 4 levels. Our study concludes that there is an association of FEA with ADH on multiple levels of CNB specimens, and follow-up surgical excision findings for FEA are clinically significant.

The spectrum of morphomolecular abnormalities of the E-cadherin/catenin complex in pleomorphic lobular carcinoma of the breast.

Pleomorphic lobular carcinoma of the breast is a high nuclear grade variant of lobular carcinoma. E-cadherin, a tumor-invasion suppressor gene, codes for a transmembrane protein that functions in intercellular adhesion. The E-cadherin protein internal domain binds with α, β, γ, and p120 catenins to anchor the E-cadherin complex to the actin cytoskeleton of the cell. The E-cadherin gene is routinely mutated in lobular neoplasia. This study examines the morphomolecular spectrum of the components of the E-cadherin-catenin complex in lobular neoplasia. Fifteen cases of pleomorphic lobular neoplasia, 8 cases of classic lobular neoplasia and 4 ductal carcinomas were studied. Normal breast epithelium and invasive ductal carcinomas all showed intense linear cell membrane immunostaining with antibodies to E-cadherin, α, β, γ, and P120 catenins. Membrane immunostaining of the catenin antibodies in lobular neoplasia was negative, except for rare cases that displayed beaded or dotlike patterns. Cytoplasmic immunostaining patterns for all lobular lesions included coarse paranuclear granules of β catenin or diffuse intense cytoplasmic staining for P120 catenin. These immunostaining patterns demonstrate that catenins α, β, γ, and p120 are routinely dislocated from the cell membrane into the cytoplasm in lobular neoplasia and that the disrupted catenin patterns parallel absence of membrane E-cadherin in all cases. The diffuse cytoplasmic immunostaining of p120 in lobular neoplasia may be useful diagnostically as a positive marker for lobular neoplasia.

Prognostic utility of the breast cancer index and comparison to Adjuvant! Online in a clinical case series of early breast cancer

IntroductionBreast Cancer Index (BCI) combines two independent biomarkers, HOXB13:IL17BR (H:I) and the 5-gene molecular grade index (MGI), that assess estrogen-mediated signalling and tumor grade, respectively. BCI stratifies early-stage estrogen-receptor positive (ER+), lymph-node negative (LN-) breast cancer patients into three risk groups and provides a continuous assessment of individual risk of distant recurrence. Objectives of the current study were to validate BCI in a clinical case series and to compare the prognostic utility of BCI and Adjuvant!Online (AO).MethodsTumor samples from 265 ER+LN- tamoxifen-treated patients were identified from a single academic institutions cancer research registry. The BCI assay was performed and scores were assigned based on a pre-determined risk model. Risk was assessed by BCI and AO and correlated to clinical outcomes in the patient cohort.ResultsBCI was a significant predictor of outcome in a cohort of 265 ER+LN- patients (median age: 56-y; median follow-up: 10.3-y), treated with adjuvant tamoxifen alone or tamoxifen with chemotherapy (32%). BCI categorized 55%, 21%, and 24% of patients as low, intermediate and high-risk, respectively. The 10-year rates of distant recurrence were 6.6%, 12.1% and 31.9% and of breast cancer-specific mortality were 3.8%, 3.6% and 22.1% in low, intermediate, and high-risk groups, respectively. In a multivariate analysis including clinicopathological factors, BCI was a significant predictor of distant recurrence (HR for 5-unit increase = 5.32 [CI 2.18-13.01; P = 0.0002]) and breast cancer-specific mortality (HR for a 5-unit increase = 9.60 [CI 3.20-28.80; P < 0.0001]). AO was significantly associated with risk of recurrence. In a separate multivariate analysis, both BCI and AO were significantly predictive of outcome. In a time-dependent (10-y) ROC curve accuracy analysis of recurrence risk, the addition of BCI+AO increased predictive accuracy in all patients from 66% (AO only) to 76% (AO+BCI) and in tamoxifen-only treated patients from 65% to 81%.ConclusionsThis study validates the prognostic performance of BCI in ER+LN- patients. In this characteristically low-risk cohort, BCI classified high versus low-risk groups with ~5-fold difference in 10-year risk of distant recurrence and breast cancer-specific death. BCI and AO are independent predictors with BCI having additive utility beyond standard of care parameters that are encompassed in AO.