CD5 POSITIVE BREAST-CARCINOMA IN A PATIENT WITH UNTREATED CHRONIC LYMPHOCYTIC-LEUKEMIA - MOLECULAR STUDIES OF CHROMOSOME 13Q

A 67 year old woman presented with a right breast lump which proved to be a grade 2 invasive ductal carcinoma with axillary lymph node metas tasis. She had a five year history of CD5 positive chronic lymphocytic leukaemia, which never required treatment. Immunoperoxidase stains fo r CD5, using the monoclonal antibody NCL-CD-54C7, showed that there wa s extensive infiltration of axillary lymph nodes with CD5 positive B l ymphocytes. Strong staining for CD5 was also seen in the carcinoma cel ls within the breast and lymph node metastases. It has recently been s uggested that there is a tumour suppresser locus in chronic lymphocyti c leukaemia at 13q12.3 near or at the BRCA2 locus. Deletion of regions on chromosome 13q containing the BRCA2 and RBI genes has also been re ported in sporadic breast cancers. These observations suggest that the re may be a link between these two diseases acting through chromosome 13, but amplification of several microsatellite repeat markers failed to show any loss of heterozygosity or repeat instability at either the se or several other loci on chromosome 13. Examination of additional s uch cases is needed to perform a more comprehensive study of the signi ficance of positive CD5 staining of breast carcinoma.