Markers of metastatic carcinoma of breast origin.

This review summarizes the three major breast-associated markers that can be of assistance in evaluating metastatic carcinomas for which a breast primary diagnosis is entertained. These markers include gross cystic disease fluid protein-15 (GCDFP-15), mammaglobin, and GATA3. The first two are cytoplasmic markers that show comparable sensitivities for breast cancer, although relatively few of the published studies have employed the same antibodies against the target molecule, making direct comparisons challenging. GATA3 is a nuclear transcription factor that shows superior sensitivity to GCDFP-15 and mammaglobin. However, the specificity of GATA3 can pose challenges, inasmuch as carcinomas of the bladder and other sites can show significant levels of positivity. Determination of the optimal panel of antibodies employed in a given clinical setting will thus depend on the non-breast tumours included in the differential diagnosis.

Clinical outcomes and prognostic markers in uterine leiomyosarcoma: a population-based cohort.

OBJECTIVE: The aim was to identify clinical parameters and immunohistochemical markers predictive of recurrence and overall survival (OS) in a community cohort of patients with primary uterine leiomyosarcoma (ULMS). METHODS/MATERIALS: All patients with new diagnosis of ULMS from 1999 to 2007 were identified from the Kaiser Permanente Northern California pathology database. A retrospective chart review was performed to gather demographic and clinical data. The primary outcomes were recurrence-free survival and OS. In addition, a subset of tumor samples was available to analyze 3 immunohistochemical markers using tissue microarray techniques; these are as follows: estrogen receptor (ER) alpha, epidermal growth factor receptor (EGFR), and Ki-67. RESULTS: Seventy-five patients with ULMS were identified, of which 63 had adequate tumor tissue available for immunohistochemical evaluation. The median follow-up for all stages was 28 months. The rate of recurrence or progressive disease was 76% for stage I patients compared with 85% for stage II to IV patients. At 3 years, 37% of stage I patients were recurrence free compared with 27% of stage II to IV patients. Overall survival for stage I patients declined from 64% to 38% between 3 and 5 years while remaining stable at 30% for stage II to IV patients. In multivariable analysis, increasing mitotic counts were associated with increased risk of recurrence (hazards ratio [HR], 3.2; P = 0.013) and a trend toward decreased OS (HR, 2.2; P = 0.10). Expression of ER (HR, 1.0), EGFR expression (HR, 1.0), and Ki-67 expression (HR, 1.0) were not predictive of recurrence or OS. CONCLUSIONS: Recurrence rate of 76% for patients with stage I ULMS was higher than previously published cohorts. Mitotic counts were associated with increased recurrence and decreased OS. Expressions of ER, EGFR, and Ki-67 were not useful for predicting overall recurrence or survival.

Epidemiology of breast cancer subtypes in two prospective cohort studies of breast cancer survivors.

INTRODUCTION: The aim of this study was to describe breast tumor subtypes by common breast cancer risk factors and to determine correlates of subtypes using baseline data from two pooled prospective breast cancer studies within a large health maintenance organization. METHODS: Tumor data on 2544 invasive breast cancer cases subtyped by estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (Her2) status were obtained (1868 luminal A tumors, 294 luminal B tumors, 288 triple-negative tumors and 94 Her2-overexpressing tumors). Demographic, reproductive and lifestyle information was collected either in person or by mailed questionnaires. Case-only odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression, adjusting for age at diagnosis, race/ethnicity, and study origin. RESULTS: Compared with luminal A cases, luminal B cases were more likely to be younger at diagnosis (P = 0.0001) and were less likely to consume alcohol (OR = 0.74, 95% CI = 0.56 to 0.98), use hormone replacement therapy (HRT) (OR = 0.66, 95% CI = 0.46 to 0.94), and oral contraceptives (OR = 0.73, 95% CI = 0.55 to 0.96). Compared with luminal A cases, triple-negative cases tended to be younger at diagnosis (P < or = 0.0001) and African American (OR = 3.14, 95% CI = 2.12 to 4.16), were more likely to have not breastfed if they had parity greater than or equal to three (OR = 1.68, 95% CI = 1.00 to 2.81), and were more likely to be overweight (OR = 1.82, 95% CI = 1.03 to 3.24) or obese (OR = 1.97, 95% CI = 1.03 to 3.77) if premenopausal. Her2-overexpressing cases were more likely to be younger at diagnosis (P = 0.03) and Hispanic (OR = 2.19, 95% CI = 1.16 to 4.13) or Asian (OR = 2.02, 95% CI = 1.05 to 3.88), and less likely to use HRT (OR = 0.45, 95% CI = 0.26 to 0.79). CONCLUSIONS: These observations suggest that investigators should consider tumor heterogeneity in associations with traditional breast cancer risk factors. Important modifiable lifestyle factors that may be related to the development of a specific tumor subtype, but not all subtypes, include obesity, breastfeeding, and alcohol consumption. Future work that will further categorize triple-negative cases into basal and non-basal tumors may help to elucidate these associations further.

Principles of analytic validation of immunohistochemical assays: Guideline from the College of American Pathologists Pathology and Laboratory Quality Center.

CONTEXT: Laboratories must validate all assays before they can be used to test patient specimens, but currently there are no evidence-based guidelines regarding validation of immunohistochemical assays. OBJECTIVE: To develop recommendations for initial analytic validation and revalidation of immunohistochemical assays. DESIGN: The College of American Pathologists Pathology and Laboratory Quality Center convened a panel of pathologists and histotechnologists with expertise in immunohistochemistry to develop validation recommendations. A systematic evidence review was conducted to address key questions. Electronic searches identified 1463 publications, of which 126 met inclusion criteria and were extracted. Individual publications were graded for quality, and the key question findings for strength of evidence. Recommendations were derived from strength of evidence, open comment feedback, and expert panel consensus. RESULTS: Fourteen guideline statements were established to help pathology laboratories comply with validation and revalidation requirements for immunohistochemical assays. CONCLUSIONS: Laboratories must document successful analytic validation of all immunohistochemical tests before applying to patient specimens. The parameters for cases included in validation sets, including number, expression levels, fixative and processing methods, should take into account intended use and should be sufficient to ensure that the test accurately measures the analyte of interest in specimens tested in that laboratory. Recommendations are also provided for confirming assay performance when there are changes in test methods, reagents, or equipment.