Stromal CD10 expression in invasive breast carcinoma correlates with poor prognosis, estrogen receptor negativity, and high grade.

CD10 is a zinc-dependent peptidase (metalloproteinase), which degrades a variety of bioactive peptides. Earlier studies suggested that CD10 expression in tumor stroma is associated with biological aggressiveness of the tumor. To date, only one study has addressed the clinical significance of stromal CD10 expression in invasive carcinoma of the breast. The aim of this confirmatory study is to evaluate stromal CD10 expression in breast carcinoma and to examine associations between CD10, clinicopathological variables, and patient outcome. Tissue microarrays, containing 438 cases of invasive breast carcinoma and 15 cases of ductal carcinoma in situ with 15 years median follow-up time, were assembled. CD10 expression was assessed by immunohistochemistry and scored as negative, weak and strong. Nonparametric correlational tests, univariate and multivariate survival analyses were performed. Stromal CD10 was preferentially expressed in invasive compared to noninvasive breast cancers (P=0.003). There were correlations between stromal CD10 expression and higher tumor grade (P=0.01) and estrogen receptor (ER) negative status (P=0.002). There was no correlation between CD10 and lymph node status, tumor size, histological subtype, progesterone receptors, and Her2 status. Stromal CD 10 expression was associated with decreased long-term disease-specific and overall survival in the entire cohort (P<0.01), and in lymph node negative (P<0.05), but not lymph node positive subset of patients. It approached prognostic significance in multivariate analysis (P=0.06) when lymph node status, tumor size, ER and Her2 were considered in the same model; and was associated with a relative risk of death of 2.8, compared to relative risk of 2.4 for lymph node positive status. Thus, stromal CD10 expression in invasive carcinoma of the breast is associated with ER negativity, higher tumor grade and decreased survival and constitutes a potential prognostic marker and a target for development of novel therapies.

Interobserver agreement and reproducibility in classification of invasive breast carcinoma: an NCI breast cancer family registry study.

The United States National Cancer Institute Breast/Ovarian Cancer Family Registry is the largest international Registry of this type; over 37 724 individuals have been enrolled to date. One activity of this Registry is the semicentralized pathologic review of tumors from all probands. Given the semicentralized nature of the review, this study was undertaken to determine the reproducibility, source(s) of classification discrepancies and stratagems to circumvent discrepancies for histologic subtyping and grading of invasive breast cancer among the reviewing pathologists. A total of 13 pathologists reviewed 35 invasive breast cancers and classified them by primary and secondary histologic type, Nottingham grade and score. Lymph-vascular space invasion, circumscribed margins, syncytial growth and lymphocytic infiltrate were also evaluated. A training session using a separate set of slides was conducted prior to the study. General agreement, in terms of category-specific kappa's and percent agreement, and accuracy of classification relative to a reference standard were determined. Classification of histologic subtype was most consistent (and accurate) for mucinous carcinoma (kappa=1.0), followed by tubular (kappa=0.8) and lobular subtypes (kappa=0.8). Classification of medullary subtype was moderate (kappa=0.4), but additional evaluation of degree of lymphocytic infiltrate, syncytial growth and circumscribed margins identified most cases. Category-specific kappa's were moderate to good for Nottingham grade (kappa=0.5-0.7), with the greatest agreement obtained in categorizing grade I (kappa=0.7), and grade III tumors (kappa=0.7). A flexible classification strategy that employs individual and combined criteria provides good interobserver agreement for invasive breast cancers with uniform, unambiguous histology and compensates for classification discrepancies in the more histologically ambiguous or heterogeneous cancers.