TP53 and neoplasm: As the extent of tumour invasion increased (mucosa and submucosa to muscularis to adventitia), the negative expression rates of BRCA2 and FHIT gradually decreased (67 to 45 to 44% vs. 56 to 35 to 33%), the p53 negative expression rates gradually decreased (56 to 50 to 50%), and the MLH1 negative expression rates initially decreased and then increased (78 to 45 to 47%).