We looked for p16 gene deletion by Southern analysis and p16 gene point mutation by single-stranded conformation polymorphism (SSCP) analysis and direct sequencing of DNA from fresh tumour samples of 35 and 33 breast carcinomas respectively. No homozygous p16 gene deletion was found in any case. A missense point mutation of the p16 gene was found in only one patient. This point mutation was absent from the patient's lymphocytes, ruling out a polymorphism or a germline mutation. These findings suggest that p16 gene alterations are rarely observed in breast carcinoma.