ESTRADIOL RECEPTORS IN COMBINATION WITH NEU OR MYC ONCOGENE AMPLIFICATIONS MIGHT DEFINE NEW SUBTYPES OF BREAST-CANCER

Amplifications of neu and c-myc were evaluated in 218 and 145 breast c ancers (BC), respectively. Oncogene amplifications were determined for the most part by Southern blot. An association between the proportion of nodes affected and the intensity of neu amplification in estadiol receptor negative (ER-) BC was found (P = 0.028), which was confirmed by the multi-factor analysis of variance (P = 0.05). A significantly g reater incidence in neu amplifications among BC with metastases was al so found (P = 0.031). A strong association (P = 0.01) between the neu and myc amplification was observed. There is a strong association betw een myc amplification and ER- BC (P < 0.01). It is concluded that (1) the combination ER-with neu amplification might define a new group of more aggressive BC, as is suggested by their associated nodal involvem ent; (2) the linkage of myc amplifications with ER- BC and high grade of neu amplification might reflect a trait of tumor aggressivity.