Marker chromosomes in a family with high incidence of cancer.

Two young sisters presenting with malignant or premalignant conditions inherited two marker chromosomes (a 13p- and a 16 with a fragile site at q22). Malignancy was reported in the family on both the mother's and father's side. According to data from the literature on similar markers and from our personal observations, a possible significance may be suggested for these markers. Search for markers must be encouraged in families with high incidence of cancer. Eventually, we may find markers which will help in understanding the processes of carcinogenesis and possibly indicate individuals at risk.