Children with xeroderma pigmentosum usually cannot carry out excision repair.

why does this makes them so susceptible to developing cancer?

a. carcinomas caused by epithelial cells that cover external and internal body surfaces lead to cancer, and one of the main mechanisms to destroy such cells is excision repair.
b. epstein-barr virus damages dna and leads to tumors, and one of the main mechanisms for repairing such damage is excision repair.
c. cancer is caused by many chemicals, that damage dna , and one of the main mechanisms for repairing such damage is excision repair.
d. pyrimidine dimers caused by exposure to sunlight can create mutations that lead to cancer, and one of the main mechanisms for repairing such defects is excision repair.