David J. Dabbs

Molecular alterations in columnar cell lesions of the breast

Columnar cell lesions of the breast include a morphologic spectrum of simple columnar cell change, columnar cell hyperplasia, columnar cell hyperplasia with atypia and ductal carcinoma in situ of micropapillary/cribriform type. Invasive carcinomas of low grade are often seen in association with this spectrum. The biologic significance of these lesions that are commonly found on breast biopsies is unknown. Three cases of formalin-fixed, paraffin-embedded breast tissues, each displaying the entire spectrum of columnar cell lesions through ductal carcinoma in situ and including foci of invasive carcinoma were microdissected at multiple sites to evaluate neoplasia progression. Minute tissue targets were microdissected (4–8/case) from unstained 4-μm thick recut paraffin sections and included non-neoplastic breast and sites of columnar cell change, hyperplasia, atypia, ductal carcinoma in situ and invasive carcinoma. Allelic imbalance for a broad panel of microsatellite markers in proximity to known tumor suppressor genes was quantitated using automated polymerase chain reaction/gel electrophoresis. Genomic loci evaluated 1p, 3p, 5q, 9p, 9q, 10q, 17p, 17q, 19q, 22q. The presence, topographic relationship and time course of mutational damage was correlated with columnar morphologic features. Detailed allelic imbalance information was obtained from each microdissection tissue target producing a detailed fingerprint of mutational damage in each case. Allelic damage was targeted predominately at 9q, 10q, 17p and 17q. Simple columnar cell change was without mutational changes and only present in one case of columnar cell hyperplasia. The remainder of the cases all show progressive accumulation of allelic damage in columnar cell changes with atypia, ductal carcinoma in situ and invasive carcinoma. The fractional mutation percentage increased progressively from columnar cell hyperplasia through invasive carcinoma. Low level of allelic imbalance was demonstrable in columnar cell lesions by the microdissection approach. A gradient of progressive mutational change could be delineated in each case manifesting allelic loss damage. Allelic loss damage appeared to preferentially target loci at 9q, 10q, 17p and 17q. The findings are consonant with the hypothesis that a select group of atypical columnar cell lesions are morphologic precursors to invasive carcinoma. Integrated molecular pathology analysis used here can help define the significance of columnar cell lesions and its role in breast cancer tumorigenesis on an individual patient basis.

Prediction of the Oncotype DX recurrence score: use of pathology-generated equations derived by linear regression analysis

Oncotype DX is a commercial assay frequently used for making chemotherapy decisions in estrogen receptor (ER)-positive breast cancers. The result is reported as a recurrence score ranging from 0 to 100, divided into low-risk (<18), intermediate-risk (18–30), and high-risk (≥31) categories. Our pilot study showed that recurrence score can be predicted by an equation incorporating standard morphoimmunohistologic variables (referred to as original Magee equation). Using a data set of 817 cases, we formulated three additional equations (referred to as new Magee equations 1, 2, and 3) to predict the recurrence score category for an independent set of 255 cases. The concordance between the risk category of Oncotype DX and our equations was 54.3%, 55.8%, 59.4%, and 54.4% for original Magee equation, new Magee equations 1, 2, and 3, respectively. When the intermediate category was eliminated, the concordance increased to 96.9%, 100%, 98.6%, and 98.7% for original Magee equation, new Magee equations 1, 2, and 3, respectively. Even when the estimated recurrence score fell in the intermediate category with any of the equations, the actual recurrence score was either intermediate or low in more than 80% of the cases. Any of the four equations can be used to estimate the recurrence score depending on available data. If the estimated recurrence score is clearly high or low, the oncologists should not expect a dramatically different result from Oncotype DX, and the Oncotype DX test may not be needed. Conversely, an Oncotype DX result that is dramatically different from what is expected based on standard morphoimmunohistologic variables should be thoroughly investigated.

Lobular neoplasia of the breast revisited with emphasis on the role of e-cadherin immunohistochemistry

Lobular neoplasia (LN) is a term that encompasses both lobular carcinoma in situ and atypical lobular hyperplasia. These lesions have been shown to constitute both risk indicators and nonobligate precursors of invasive breast cancer, they are relatively uncommon, and are most often identified in specimens taken for other reasons. Their incidence has increased in the last 2 decades, and novel variants, including a pleomorphic type, have been described. Loss of E-cadherin expression is recognized as a hallmark diagnostic feature of LN and invasive lobular carcinomas, and immunohistochemical (IHC) analysis using anti-E-cadherin antibodies has been proven to be a useful method to differentiate between lobular and ductal lesions. The frequent use of E-cadherin IHC analysis in routine diagnostic histopathology, however, has resulted in confusion with regard to the actual value of IHC with antibodies against E-cadherin and other proteins of the cadherin-catenin complex. This review provides an update on recent clinicopathologic and molecular data on LN and invasive lobular carcinoma and a discussion about the use and limitations of IHC with E-cadherin in diagnostic breast pathology.

Renal vascular smooth muscle proliferation in neurofibromatosis

An unusual vascular lesion was seen in a 14-year-old white boy with renal vascular hypertension and neurofibromatosis. Microscopically, nodular intimal and medial proliferations of spindle-shaped cells involved arteries, arterioles, and veins of all caliber within the renal parenchyma. Immunoperoxidase studies indicated these cells to have characteristics of smooth muscle, and this finding was confirmed by ultrastructural examination. Despite the generalized nature of the process in the biopsy sample, the patients hypertension responded well to surgical treatment.

Invasive Lobular Carcinoma Cell Lines Are Characterized by Unique Estrogen-Mediated Gene Expression Patterns and Altered Tamoxifen Response

Invasive lobular carcinoma (ILC) is a histologic subtype of breast cancer that is frequently associated with favorable outcomes, as approximately 90% of ILC express the estrogen receptor (ER). However, recent retrospective analyses suggest that patients with ILC receiving adjuvant endocrine therapy may not benefit as much as patients with invasive ductal carcinoma. On the basis of these observations, we characterized ER function and endocrine response in ILC models. The ER-positive ILC cell lines MDA MB 134VI (MM134) and SUM44PE were used to examine the ER-regulated transcriptome via gene expression microarray analyses and ER ChIP-Seq, and to examine response to endocrine therapy. In parallel, estrogen response was assessed in vivo in the patient-derived ILC xenograft HCI-013. We identified 915 genes that were uniquely E2 regulated in ILC cell lines versus other breast cancer cell lines, and a subset of these genes were also E2 regulated in vivo in HCI-013. MM134 cells were de novo tamoxifen resistant and were induced to grow by 4-hydroxytamoxifen, as well as other antiestrogens, as partial agonists. Growth was accompanied by agonist activity of tamoxifen on ER-mediated gene expression. Though tamoxifen induced cell growth, MM134 cells required fibroblast growth factor receptor (FGFR)-1 signaling to maintain viability and were sensitive to combined endocrine therapy and FGFR1 inhibition. Our observation that ER drives a unique program of gene expression in ILC cells correlates with the ability of tamoxifen to induce growth in these cells. Targeting growth factors using FGFR1 inhibitors may block survival pathways required by ILC and reverse tamoxifen resistance.

Semiquantitative GATA-3 Immunoreactivity in Breast, Bladder, Gynecologic Tract, and Other Cytokeratin 7–Positive Carcinomas

OBJECTIVESnTo evaluate GATA-3 immunohistochemical expression semiquantitatively in breast, gynecologic, gastric, pancreatic-biliary tract, urothelial, and vulvar/cervical squamous cell carcinomas.nnnMETHODSnGATA-3 expression was evaluated by immunohistochemistry in 198 invasive breast carcinomas on tissue microarrays. Tissue microarrays of other tissues included 144 gynecologic tumors, 28 bladder carcinomas, 63 cholangiocarcinomas, 20 pancreatic carcinomas, and 62 gastric carcinomas. Full tissue sections of 10 invasive squamous cell carcinomas were also stained. GATA-3 expression was semiquantitatively scored using an H-score method. H-score greater than 10 was considered a positive result.nnnRESULTSnOf 186 breast carcinomas, 95% were positive (mean H-score of 217). GATA-3 expression was uncommon in 139 nonsquamous gynecologic tumors, with often weak reactivity (mean H-score <50) seen in 18% of endocervical, 7% of endometrial, and 10% of ovarian tumors. Six (60%) of 10 squamous cell carcinomas expressed GATA-3 (mean H-score of 102). Of 22 urothelial carcinomas, 95% expressed GATA-3 (mean H-score of 170). A few cholangiocarcinomas (3%), pancreatic adenocarcinomas (10%), and gastric carcinomas (2%) weakly expressed GATA-3 (mean H-score <50).nnnCONCLUSIONSnStrong GATA-3 expression is a reliable marker of primary breast carcinoma in the appropriate clinical context. GATA-3 reactivity in around 70% of triple-negative breast carcinomas is also clinically useful. Significant reactivity in gynecologic squamous cell carcinomas suggests that GATA-3 alone cannot reliably distinguish these tumors from urothelial carcinoma.

Interobserver Agreement Among Pathologists for Semiquantitative Hormone Receptor Scoring in Breast Carcinoma

The American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guidelines recommend reporting of hormone receptor test results in a semiquantitative manner. This study used 74 resected estrogen receptor (ER)-positive invasive breast cancers to determine reproducibility of semiquantitative scoring of hormone receptors using the H-score method. Four pathologists independently scored each slide. Agreement among observers was analyzed via Fleiss κ statistics on ER and progesterone receptor (PR) categorical scores. Intraclass correlation coefficient (ICC) was used to estimate the interobserver agreement for ER and PR H-scores on a continuous scale (0-300). There was 100% agreement for categorical ER results (κ = 1) and 97% agreement (κ = 0.823, P < .001) for categorical PR results. For quantitative H-scores, ICC agreement was 0.85 (95% confidence interval [CI] = 0.79-0.90) for ER and 0.87 (95% CI = 0.82-0.92) for PR. Because the H-score provides a continuous measure of tumor hormone receptor content, we suggest universal adoption of this method.

Invasive lobular carcinoma of the breast: patient response to systemic endocrine therapy and hormone response in model systems.

Invasive lobular carcinoma of the breast (ILC) represents 10-15% of all newly diagnosed breast cancers, affecting ∼30,000 women annually in the United States. However, ILC is critically understudied as a breast cancer subtype. Though the vast majority of ILC are estrogen receptor-positive and present with overall favorable biomarkers, ILC patients do not benefit from improved outcomes versus other breast cancer patients. Patient outcomes, in particular in response to endocrine therapies, are not well understood in ILC, due in large part to the lack of prospective identification in large clinical trials. Further, there is a lack of laboratory models to study cell signaling, hormone response, and endocrine resistance in ILC. In this review, we provide an overview of clinicopathological features of ILC tumors, discuss issues with clinical management, and highlight the disconnect between ILC biomarkers and patient outcomes. We review currently available data on ILC patient outcomes, with a focus on response to endocrine therapy. Additionally, we describe currently available laboratory models for understanding hormone response in ILC cells, and review current data on these model systems. The promise for new insight into ILC, based on extensive representation of the disease in recent large scale genomic studies, is also discussed. Increasing understanding of endocrine response in ILC represents a critical area for future research to improve patient outcomes for this understudied breast cancer subtype.

Impact of progesterone receptor semiquantitative immunohistochemical result on Oncotype DX recurrence score: a quality assurance study of 1074 cases.

Decreased or absent progesterone receptor expression in invasive breast carcinoma is a marker for an adverse prognosis. As part of an ongoing quality assurance study, this study evaluated the relationship between Oncotype DX recurrence score and progesterone receptor immunohistochemical result within each Nottingham tumor grade in 1074 cases of invasive breast carcinoma for which an Oncotype DX recurrence score was available. In addition to a statistically significant association between Nottingham grade and Oncotype DX recurrence score categories (P<0.001), an inverse relationship was identified between progesterone receptor expression measured by modified H-score semiquantitation and Oncotype DX recurrence score that was independent of Nottingham tumor grade. The Oncotype DX recurrence score relies heavily on parameters already available from routine pathologic examination, and consideration of progesterone receptor status may aid in selection of patients most likely to benefit from ancillary testing.

Microcalcification Is an Important Factor in the Management of Breast Intraductal Papillomas Diagnosed on Core Biopsy

The follow-up excision (FUE) results were analyzed from 370 cases diagnosed as intraductal papilloma on breast core needle biopsy (CNB) with no history of malignancy or other risk factors. Of these cases, 98.6% were rendered a Breast Imaging Reporting and Data System score of 4 on mammography before the CNB. Fifty-one cases (13.8%) were found to have microcalcifications on microscopic examination of CNB. A total of 7 (1.9%) of 370 cases were upgraded to invasive carcinoma, ductal carcinoma in situ, or pleomorphic lobular carcinoma in situ on FUE. Six of 51 (11.8%) cases with microcalcifications found on imaging and CNB were upgraded to ductal carcinoma in situ or invasive carcinoma, whereas only 1 (0.3%) of 319 cases without microcalcifications was upgraded to pleomorphic lobular carcinoma in situ (P = .003). Results of a multivariate analysis adjusted for age confirmed that microcalcifications was a risk factor for upgrading to cancer, independent of age. Our results indicate that surgical excision is required for intraductal papilloma diagnosed on CNB if microcalcifications are present. However, excision may not be required for those who have no microcalcifications on CNB and no other known risk factors.