HIGH-FREQUENCY OF ALLELIC IMBALANCE AT CHROMOSOME REGION 16Q22-23 IN HUMAN BREAST-CANCER - CORRELATION WITH HIGH PGR AND LOW S-PHASE

The loss of genetic material from a specific chromosome region in tumo rs suggests the presence of tumor-suppressor genes. Loss of heterozygo sity (LOH) or allelic imbalance (Al) on the long arm of chromosome 16 is a known event in sporadic breast cancer. To locate the commonly del eted regions, and therefore (a) candidate tumor-suppressor gene(s), a deletion map of chromosome 16 was made, using 10 microsatellite marker s on 150 sporadic breast tumors. The 3 smallest regions of overlap (SR O) were detected on the long arm of chromosome 16. Allelic imbalance w as observed with at least one marker in 67% of the tumors. One marker, D16S421, at the 16q22-23 region, showed the highest allelic imbalance , 58%. Tumors with and without Al on I bq were tested for correlation with clinico-pathological features of the tumors such as estrogen- and progesterone-receptor content (ER and PgR), age at diagnosis, tumor s ize, node status, histological type, S-phase fraction, Al on chromosom e 3p, and ploidy. A correlation was found between Al on 16q and high P gR content, also low S-phase fraction (99% confidence limits). A compa rison of tumors with and without Al at the D16S421 marker locus reveal ed a slight correlation with high PgR content. The survival data showe d no difference between patients with Al on 16q and those with a norma l allele pattern on the long arm of chromosome 16. (C) 1995 Wiley-Liss , Inc.