Truncated proteins are easily discriminated from full size.RESULTS: Three BRCA 1 gene alterations were identified in the investigated group of women suffering from ovarian or breast cancer. One asymptomatic person--carrier of BRCA 1 gene mutation--was identified in this study. She was daughter of a woman, a carrier of BRCA 1 gene mutation, with early onset of breast cancer and positive family history.CONCLUSIONS: BRCA 1 and BRCA 2 gene mutations are of particular importance in the increasing risk of ovarian cancer and early onset of breast cancer as well as some other malignancies.