For which ONE of the following tumours is there a definite genetic basis in a proportion of cases?

The answer is C. Polyposis (adenomatosis) coli has a Mendelian dominant inheritance, half the members of the family developing colonic polyps with resultant colonic carcinoma in early adult life.

Some families have similar tumour, i.e., bronchial carcinoma or gastric carcinoma occurring in siblings and in several generations without definite evidence of a genetic predisposition.

Vaginal (clear cell) carcinoma (E) may develop in teenage girls whose mothers took diethylstilbestrol in pregnancy.