In lymph node‐negative invasive breast carcinomas, specific chromosomal aberrations are strongly associated with high mitotic activity and predict outcome more accurately than grade, tumour diameter, and oestrogen receptor

Abstract

The objectives of this study were to analyse whether specific chromosomal gains and losses in lymph node-negative breast cancer correlate with other features and to evaluate their prognostic value. Seventy-six lymph node-negative breast carcinomas (median follow-up 46 months; range 9-105 months) were used. Histological grade, tumour type, maximal tumour diameter, oestrogen/progesterone receptor (ER/PR), mitotic activity index (MAI), and mean nuclear area (MNA) were assessed. Whole genome DNA analysis was performed by comparative genomic hybridization (CGH). Chromosomal aberrations were compared with classical and other prognostic features. Kaplan-Meier curves and multivariate survival analysis (Cox model) were used to assess the prognostic value of the CGH and other data. Fifteen (21.4%) out of 70 patients (six cases were lost to follow-up) developed locoregional (n=3) or distant metastases (n=12). The following criteria were prognostic for (any) recurrence (in decreasing significance): 3q gain, simultaneous gain at 1q and 8q, MAI < versus > or =10, MNA < versus > or =63 microm. Loss of 1p occurred significantly more often in the large group of ductal breast carcinomas with a MAI > or =10 (n=38) than in cancers with a MAI<10. Moreover, 8/15 (53%) patients with recurrences had a gain at 3q, as opposed to three (5.5%) of the 55 recurrence-free patients. This association was even stronger in ductal carcinomas (hazard ratio=10.9, p<0.0001). Cox regression revealed that the 3q gain was the strongest prognostic factor; other features did not have additional prognostic value. In conclusion, loss of 1p is associated with a high MAI. A gain of 3q is a stronger predictor of recurrence than grade, MAI, and other features in invasive breast cancers.