The combination of tumour suppressor activity of hENT3 and presence of breast and bladder cancer (at ages 43 and 46 years respectively) in the proband of family 1 (VII: 7) led us to speculate that SLC29A3 mutations might predispose to epithelial cancers and/or be mutated in sporadic breast and bladder cancer. Here, SLC29A3 is linked to neoplasm.