p73, a new member of the p53 family, has been mapped to chromosome 1p 36, a region where loss of heterozygosity (LOH) is frequently observed in primary human
tumors. Allelic loss studies involving the 1p arm in
breast carcinomas offer rates ranging from 13% to 75%, depending on the genetic interval being studied. We investigated LOH in an intragenic microsatellite marker, and those centromerically flanking the p73 gene, at 1p 36, and their correlations with patient age and 10 pathologic parameters in a series of 193
breast carcinomas. The LOH analysis was performed by amplifying
DNA by PCR, using the five markers of the 1p 36 region (p73P1, D1S2694, D1S214, D1S2666 and D1S450). LOH was found in at least one of these markers in 27% of
tumors. When we established the comparison between
tumors with and without LOH and the distribution of the 10 pathologic parameters considered, we observed statistically significant differences in association with higher histologic grade (p = 0.02), more advanced pathological stage (p = 0.02), peritumoral vessel involvement (p = 0.04) and poorly differentiated
carcinomas (p = 0.01), as well as in
tumors that concomitantly exhibited
lymph node metastases, peritumoral vessel involvement and absence of
steroid receptors (p = 0.02). These data suggest that LOH in the p73 region could be pathogenically related to
breast cancer and possibly to a poor
tumor prognosis.