The loss of the gene cluster is involved in the development of cancers such as chronic lymphocytic leukaemia (CLL), pituitary adenomas, and prostate carcinoma.13, 14 Here, we determined that the loss of miR‐15a/16 was associated with induction of IL‐10‐producing B cells under tumour microenvironment. This evidence concerns the gene IL10 and prostate carcinoma.