Prostate cancer occurring in identical twins: A case report

Prostatic cancer, which is an age‐associated and androgen‐dependent cancer, is the most common malignancy in males in the United States. Although the etiologic factors in prostate cancer are not clear, increased male sexual activity on a hormonal basis [1], a viral‐venereal connection [2], and air pollution [3] have been hypothesized. Genetic factors are suggested by racial variation [4] and by familial incidence of prostate cancer; however, with family studies alone, it is not possible to decide if it is genetically determined or if it is due to a greater than average similarity in environment. For cancer in general, the study of concordance rates among populations of twins has failed to establish a precise role for inheritance, but more detailed study of individual types of tumors in twins may reveal a genetic connection [5]. The following report describes the second recorded monozygotic twin set concordant for prostate cancer.