Is there a connection between breast cancer and apl leukemia? there are two cases of breast two cases of leukemia in my cousins family.

No: There is no association or reported instances of leukemia associated with breast cancer. The closest that one can find is a rare association between lymphoma, probably arising in a intramammary lymph node and carcinoma in the same breast . There is the possibity that the cause is the MMTV virus that has entered the Wnt-1 gene to overproduce B-catenin.