Hind Nassar

Most Basal-like Breast Carcinomas Demonstrate the Same Rb−/p16+ Immunophenotype as the HPV-related Poorly Differentiated Squamous Cell Carcinomas Which They Resemble Morphologically

Basal-like carcinomas (BLCs) of the breast share discriminatory morphologic features with poorly differentiated high-risk human papilloma virus (HPV)-related squamous cell carcinomas of the oropharynx, penis, and vulva. Because HPV E7 protein inactivates the retinoblastoma (Rb) protein, diffuse p16 expression is a surrogate marker for these high-risk HPV-related carcinomas. HPV E6 protein also inactivates p53, further compromising the G1-S cell cycle checkpoint. The Rb/p16/p53 immunohistochemical profile of BLC of the breast has not been well characterized. Tissue microarrays containing 71 invasive ductal carcinomas (IDCs) of the breast were immunolabeled for p16, Rb, p53, and Ki-67. The cases included 4 distinct groups of IDCs having surrogate immunohistochemical profiles corresponding to categories defined by gene expression profiling (17 luminal A, 7 luminal B, 14 HER-2+, and 21 BLC), along with 12 unclassifiable triple negative carcinomas (UTNCs). Twenty-five of the 71 IDC were Rb negative/p16 diffuse positive (Rb−/p16+). These included 15 of 21 BLC and 9 of 12 UTNC, but only 1 of 14 HER-2 positive cases and none of the 17 luminal A or 7 luminal B cases (P<0.01, BLC or UTNC vs. others). Six of the Rb−/p16+ IDC also had a significant ductal carcinoma in situ component. The ductal carcinoma in situ in 4 of these 6 cases showed the same Rb−/p16+ phenotype as the associated IDC. BLC and UTNC had the highest Ki-67 indices of the 5 groups, even when matched for grade. The Rb−/p16+ phenotype and the Rb−/p16+/p53 overexpressing phenotype correlated with increased proliferation within the BLC group. In conclusion, BLC and UTNC, but not HER-2, luminal A, or luminal B carcinomas, frequently demonstrate an Rb−/p16+ phenotype, similar to the HPV-related squamous cell carcinomas that BLC resemble morphologically. This subset may represent a more homogenous group than BLC as defined currently.

Relationship between molecular subtype of invasive breast carcinoma and expression of gross cystic disease fluid protein 15 and mammaglobin.

We investigated the expression of gross cystic disease fluid protein 15 (GCDFP) and mammaglobin (MGB) by immunohistochemical analysis in 71 invasive breast carcinomas (IBCs) subtyped into luminal (A and B), HER2, basal-like carcinoma (BLC), and unclassified triple-negative carcinoma (UTNC) by established surrogate immunohistochemical profiles. GCDFP and MGB were less likely to be expressed in BLC than in HER2 cancers (P = .000021 and P = .013, respectively) or luminal cancers (P = .00002 and P = .00008, respectively). However, the difference in GCDFP or MGB expression between HER2 and luminal cancers was not significant (P = 1.0 and P = .671, respectively). Our results suggest that luminal cancers demonstrate similar degrees of apocrine differentiation as HER2 cancers. Most BLCs and UTNCs are negative for MGB and GCDFP. Correlation with clinical findings may be needed to exclude the possibility of a metastasis to the breast when BLCs or UTNCs are encountered in a limited sample such as a core biopsy sample.

MYC gene amplification is often acquired in lethal distant breast cancer metastases of unamplified primary tumors.

In breast cancer, amplification of MYC is consistently observed in aggressive forms of disease and correlates with poor prognosis and distant metastases. However, to date, a systematic analysis of MYC amplification in metastatic breast cancers has not been reported. Specifically, whether the MYC amplification status may change in metastases in comparison to the corresponding primary breast tumor, and potential variability among different metastases within the same patient have also not been assessed. We generated single patient tissue microarrays consisting of both primary breast carcinomas and multiple matched systemic metastases from 15 patients through our previously described rapid autopsy program. In total, the 15 tissue microarrays contained 145 primary tumor spots and 778 spots derived from 180 different metastases. In addition, two separate tissue microarrays were constructed composed of 10 matched primary breast cancers and corresponding solitary metastases sampled not at autopsy but rather in routine surgical resections. These two tissue microarrays totaled 50 primary tumor spots and 86 metastatic tumor spots. For each case, hormone receptor status, HER2/neu, EGFR and CK5/6 expression were assessed, and the cases were characterized as luminal, basal-like or HER2 based on published criteria. Both fluorescence in situ hybridization and immunohistochemistry for MYC was performed on all cases. Of the 25 cases, 24 were evaluable. While 4 of 24 primary tumors (16%) demonstrated MYC amplification, an additional 6 (25% of total evaluable cases) acquired MYC amplification in their systemic metastases. Of note, there was remarkably little heterogeneity in MYC copy number among different metastases from the same patient. MYC immunoreactivity was increased in metastases relative to matched primaries in the surgical cohort, although there was no perfect correlation with MYC amplification. In conclusion, amplification of MYC is a frequent event in breast cancer, but occurs more frequently as a diffuse, acquired event in metastatic disease than in the corresponding primary. These observations underscore the importance of MYC in breast cancer progression/metastasis, as well as its relevance as a potential therapeutic target in otherwise incurable metastatic disease.

Incidental minimal atypical lobular hyperplasia on core needle biopsy: correlation with findings on follow-up excision.

IntroductionAtypical lobular hyperplasia (ALH), often an incidental finding in breast core biopsies, is largely considered to be a risk factor for carcinoma rather than a direct precursor. However, management of ALH is controversial. We review our experience with incidental minimal ALH on core biopsy, and correlate with excision and follow-up results. DesignWe evaluated all cases of ALH on core biopsy from 1999 to 2009 from our institution, focusing on cases with ≤3 foci of ALH (minimal), paired excision, and no other lesion on the core biopsy that by itself would require excision. Cases with discordant clinical/radiologic impressions, suggesting that a suspicious lesion had been missed on biopsy, were excluded. Therefore, the excisions were performed because of the diagnosis of ALH. ResultsOf 56 cases with ALH on biopsy and paired excision, 42 showed minimal ALH. On excision, 26 had residual ALH and 13 were benign. Three cases had other atypical lesions: lobular carcinoma in situ (2 cases) and mild atypical ductal hyperplasia separate from the biopsy site (1 case). On follow-up, only 1 patient developed subsequent ALH in the same breast. No other ipsilateral lesions were later diagnosed (mean follow-up 3.2 y). ConclusionsNo case with ALH on biopsy had a lesion on excision requiring further treatment, suggesting that these patients can be managed more conservatively. Furthermore, no patients were diagnosed with a higher grade lesion in the same breast on follow-up. We propose that, if there is close radiologic correlation and follow-up, minimal incidental ALH on core biopsy (≤3 foci) does not require excision.

The alternative lengthening of telomeres phenotype in breast carcinoma is associated with HER-2 overexpression

Approximately 10–15% of human cancers do not show evidence of telomerase activity, and a subset of these maintain telomere lengths by a recombination-based mechanism termed alternative lengthening of telomeres (ALT). The ALT phenotype, relatively common in certain sarcomas and germ cell tumors, is very rare in carcinomas. In this study we describe evidence for the ALT phenotype in molecular subclasses of breast carcinoma, specifically a subset of cancers with HER-2 overexpression. Tissue microarrays were created from 71 invasive ductal carcinomas of the breast categorized into subclasses, and telomere lengths were directly assessed using fluorescence in situ hybridization with combined promyelocytic leukemia (PML) protein immunofluorescence. The ALT phenotype was identified in 3 of 21 HER-2-positive cases, but in none of the other 50 cases (P=0.023). This is the first direct observation of this mechanism of telomere maintenance in breast carcinoma unrelated to Li–Fraumeni syndrome. The correlation of the ALT phenotype with HER-2 positivity, both of which involve abnormal DNA amplification, suggests a possible common underlying mechanism. This telomere phenotype confers a poor prognosis in some cancers; two of the three cases in our study showed rapid tumor progression, possibly suggesting that it may adversely affect outcome in breast carcinoma as well. As cancers using the ALT pathway are predicted to be resistant to therapies based on telomerase inhibition, these results may have therapeutic consequences.

Ductal carcinoma in situ in African American versus Caucasian American women: analysis of clinicopathologic features and outcome.

Invasive breast carcinoma has a more aggressive phenotype and a higher mortality rate in African American (AA) than in Caucasian American (CA) women. The characteristics of ductal carcinoma in situ (DCIS) in the AA population have not been extensively studied.

Pseudoangiomatous Stromal Hyperplasia (PASH) of the Breast With Foci of Morphologic Malignancy: A Case of PASH With Malignant Transformation?

Pseudoangiomatous stromal hyperplasia (PASH) is a benign proliferation of the hormonally responsive, specialized mammary stroma characterized by slit-like pseudovascular spaces lined by bland spindle cells. It is usually an incidental microscopic finding but in some cases it may present as a slowly growing mass. A malignant counterpart for this lesion has not been reported. We describe a case of PASH with foci of malignant histologic features presenting as a slowly growing mass in a 30-year-old woman. The previously reported variants of PASH and the other mammary stromal lesions related to PASH are also discussed. This is perhaps the first case of PASH with foci of malignant histologic features reported in the literature and represents a rare sarcoma derived from specialized hormonally responsive mammary stroma.

Serial analysis of gene expression of lobular carcinoma in situ identifies down regulation of claudin 4 and overexpression of matrix metalloproteinase 9

IntroductionAlthough lobular carcinoma in situ (LCIS) has traditionally been viewed as a marker of breast cancer risk, recent clinical, pathological and genetic analyses have supported the concept that LCIS is a low risk, direct precursor of invasive lobular carcinoma. Global gene expression profiling of LCIS has not been performed.MethodsWe analysed the comprehensive gene expression profile of a unique case of mass-forming LCIS using serial analysis of gene expression (SAGE). This SAGE library is publicly available online. By comparing the gene expression profile of LCIS to that of benign breast epithelium and stroma, we identified several genes up and down regulated in LCIS. Differential expression of selected genes not previously studied in LCIS was validated at the protein level by immunohistochemistry and at the RNA level by quantitative reverse transcriptase PCR (RT-PCR).ResultsWe identified down regulation of claudin 4 and overexpression of matrix metalloproteinase 9 in LCIS relative to normal breast epithelium and stroma. We validated these findings by immunohistochemistry in a separate series of 11 and 19 LCIS cases, respectively. Overexpression of matrix metalloproteinase 9 was further confirmed by quantitative RT-PCR analysis of the index case.ConclusionsWe have created the first global gene expression profile of LCIS, and demonstrated down regulation of cell junction proteins (an expected result) and overexpression of matrix metalloproteinase 9 (an unexpected result). Additional analysis of this data made available as an online resource should facilitate further molecular characterisation of LCIS.

Pathologic Complete Response to Preoperative Sequential Doxorubicin/Cyclophosphamide and Single-Agent Taxane With or Without Trastuzumab in Stage II/III HER2-Positive Breast Cancer

BACKGROUND Four major clinical trials have established that trastuzumab added to adjuvant systemic chemotherapy for women with HER2+ breast cancer significantly improves disease-free and overall survival compared with chemotherapy alone. We evaluated pathologic complete response (pCR) rate and cardiac safety of preoperative doxorubicin and cyclophosphamide followed by a taxane with or without trastuzumab. PATIENTS AND METHODS We reviewed pCR rate and change in left ventricular ejection fraction in women with operable HER2+ breast cancer (defined as immunohistochemical 3+ or fluorescence in situ hybridization ratio > or = 2.2) who were treated between 2002 and 2008 with doxorubicin and cyclophosphamide followed by a taxane with or without trastuzumab before definitive breast surgery. RESULTS We identified 33 patients, of whom 42.4% received preoperative chemotherapy without trastuzumab and 57.6% of whom received trastuzumab with chemotherapy. The pCR rates were 28.6% and 52.6% in the group that received chemotherapy alone or with trastuzumab, respectively (odds ratio, 2.78; 95% CI, 0.64-12.1; P = .173). Severe cardiac events or treatment delays as a result of cardiac toxicity were not observed. With a median follow-up time of 14 months, 21.4% of patients in the non-trastuzumab group and 10.5% in the trastuzumab group had disease recurrence. CONCLUSION Sequential administration of preoperative doxorubicin and cyclophosphamide followed by a taxane and trastuzumab combination is safe in women with primary operable HER2+ breast cancer and is associated with a high pCR rate. Large randomized phase III clinical trials are evaluating the role of preoperative trastuzumab when added to anthracycline- and/or taxane-based regimens.

Heterogeneity of Bcl-2 expression in metastatic breast carcinoma

Bcl-2 is an antiapoptotic protein that promotes cell survival, but also may block proliferation. In breast cancer, bcl-2 expression correlates with favorable prognosis and estrogen receptor (ER) positivity. However, experimental data have paradoxically suggested that bcl-2 promotes chemoresistance and metastasis. A direct and comprehensive comparison of bcl-2 expression between primary breast carcinomas and paired distant metastases has not been performed. We completed rapid autopsies on 17 patients with archived primary tumors and metastatic breast carcinoma, and created single-patient tissue microarrays containing each patients primary tumor and matched metastases. Expression of bcl-2, ER, progesterone receptor, and HER-2 in primary tumors and matched metastases were compared by immunohistochemistry. All 11 ER-positive cases showed bcl-2 labeling in the primary tumor, whereas only 3 of 6 ER-negative cases did (P=0.029). In 10 cases, bcl-2 labeling in metastases was similar to that of the primary, although 3 cases showed significant variation among metastases. In six other cases, bcl-2 labeling was lost or significantly diminished in metastases. Five of the latter cases were Luminal A (ER-positive, HER-2-negative) primaries, three of which lost hormone receptors in metastases. Only 1 of 17 cases showed an increase in bcl-2 labeling in metastases compared with the paired primary tumor. In conclusion, bcl-2 is infrequently upregulated in metastatic breast carcinoma. Instead, downregulation of bcl-2 expression may occur in the setting of hormone therapy resistance. Our findings call into question the potential utility of anti-bcl-2 therapy in metastatic breast cancer.