MTAP and breast cancer: However, deletion of 9p21.3 is considered an unfavorable chromosomal aberration in renal cell carcinoma.[27] There are at least 3 TSGs at 9p21.3: CDKN2A, CDKN2B, and MTAP, and deletion of 9p21.3 may predispose an individual to melanoma, neural system tumors, hematologic malignancies, astrocytoma, breast cancer, and chordoma.[28–30] All 3 TSGs were included in the lost segment in the current patient, suggesting that the somatic microdeletion of 9p21.3 may have contributed to the occurrence of malignancy in this case.