PARP1 and leukoplakia: Significantly amplified genes (BTBD7, CAMSAP1L1, CHRDL2, FBXO7, GMPK2, HBEGF, IRF9, KHDRBS1, NPM3, PAIP2, PARP1, RAB1A, REC8 and TBRG4) and significantly deleted genes (CSMD1 and MYO5B) were detected in progressive leukoplakia and OSCCs, and not in non-progressive lesions.