PTPRK and neoplasm: A number of genes demonstrated reduced copy number and expression in KRAS mutant tumours, including putative tumour suppressor genes (FOXO3, EXTL2, PPP2R1B), negative regulators of the receptor tyrosine kinase oncogenic pathways (PTPRK, DGKZ, NCAM1), and negative regulators of Ras (EPHB2).