We have previously described a novel family of human endogenous retroviral genomes. The nucleotide sequence of the prototype (HLM-2) has been determined. The results confirm our earlier conclusion based on blot hybridization studies that this class of viral genomes is a mosaic of sequences related to different classes of infectious retroviruses. This novel class of endogenous retroviruses is unrelated to mammalian type C retroviruses. The HLM-2 and the related HLM-25 proviral genomes have been shown to be located on respectively human chromosomes 1 and 5. Since the chimpanzee cellular genome also contains these two proviral genomes the viral integration events must have occurred prior to the divergence of these species. We have begun to determine the genetic alterations associated with breast carcinomas. This study has shown: (1) significant correlation (p less than .001) between rare alleles of c-Hras-1 and breast cancer patients, (2) the frequent loss of c-Hras-1 allele correlates with histopathological grade III tumors (p less than .02), loss of estrogen and/or progesterone receptors (p less than .01), patients which later developed a distal metastasis (p less than .05), and (3) amplification or rearrangement of c-myc correlates (p less than .02) with patients over 51 years of age.
