RB1 and neoplasm: Three chromosomal regions were of interest, including a deletion of 5q12–21 found in 26% of tumors, a deletion of 13q14–21 also found in 26% of tumors that contains the RB1 tumor suppressor, and amplification at 1p34 present in 39%, which contains the L-Myc (MYCL1) oncogene [67].