Table 1.

Gene targets associated with colorectal neoplasia in inflammatory bowel disease

Gene (chromosomal locus studies)	Function	Prevalence in IBD-related CRC	Timing in the dysplasia–cancer sequence	Pathogenesis or mechanisms of mutation	References
APC (5q21)	Tumor suppressor gene (cell adhesion)	Rare (<15%)	Late	HGD, CRC	Greewald et al. [191], Kern et al. [192], Tarmin et al. [193], Redston et al. [194], Willenbucher et al. [195], Tomlinson et al. [200], Willenbucher et al. [234], Umetani et al. [196], Aust et al. [197], Aust et al. [198], Aust et al. [199], Maia et al. [235]
DCC/DPC (18Q21)	Tumor suppressor gene (cell adhesion)	Common (>50%0	Early	Dysplasia	Lei et al. [201], Willenbucher et al. [195], Hoque et al. [202], Tomlinson et al. [200], Willenbucher et al. [234], Aust et al. [197]
TP53 (17p13)	Tumor suppressor gene (cell cycle, apoptosis)	Common (>50%)	Early	May precede dysplasia	Burmer et al. [203], Greewald et al. [191], Yin et al. [204], Harpaz N et al. [205], Brentnall et al. [206], Chaubert et al. [207], Klump et al. [208], Holzman et al. [209], Rabinovitch et al. [210], Aust et al. [197], Wong et al. [211], Hussain et al. [212], Maia et al. [235], Nathanson et al. [213]
CDKN2A (9P21)	Tumor suppressor gene (cell cycle inhibitor)	Frequent	Early	Hypermethylation	Hsieh et al. [214], Issa et al. [215]
CDKN2A (9P21)	Tumor suppressor gene (indirect p53 regulator)	Frequent	Early	Hypermethylation	Sato et al. [216], Moriyama et al. [217]
CDKN2A (12p13)	Tumor suppressor gene (cell cycle regulation)	Under-expressed in CRC			Walsh et al. [218]
E-cadherin	Tumor suppressor gene (cell adhesion)	Frequent	Early	Hypermethylation	Ilyas et al. [219], Tomlinson et al. [200], Wheeler et al. [220], Azarschab et al. [221], Van Dekken et al. [222]
K-ras (12p12)	Oncogene (cell cycle regulation)	Uncommon (<25%)	Late	HGD, CRC	Burmer et al. [223], Meltzer et al. [224], Bell et al. [225], Chaubert et al. [207], Redston et al. [194], Umetani et al. [196], Lyda et al. [226], Holzmann et al. [227], Aust et al. [228]
C-src TGFβR2 RII	Oncogene TGF-β1 receptor gene	Intermediate MSI-related CRC (less common than sporadic MSI CRC)	Unknown Unknown	LGD to HGD MSI	Cartwright et al. [229], Souza et al. [230]
MSH2 (2p22)	DNA mismatch repair gene	MSI-related CRC	Unknown	MSI	Brentnall et al. [231], Noffsinger et al. [232]
MLH1	DNA mismatch repair gene	Intermediate MSI-related CRC (less common than sporadic MSI CRC)	Unknown	MSI, hypermethylation	Fleisher et al. [233]

Abbreviations: APC adenomatous polyposis coli, CRC colorectal carcinoma, DCC deleted in colon cancer, HGD high-grade dysplasia, LGD low-grade dysplasia, MSI microsatellite instability, TGF transforming growth factor