In colon cancer, normal colon tissue and blood cells have altered telomere lengths

Telomere length (TL) shortened occurs in colorectal carcinogenetic process. Our objective is to determine if it is only a local fact or there are alterations in normal colon cells and in other body cells.

TL of tumoral and normal mucosa and leukocytes of 40 patients operated of colorectal cancer (CRC) and 40 control patients with normal colonoscopy were measured by Southern-blot. Groups were matched by the same localization as tumors, sex, and age.

In CRC patients, TRFL (Telomere Repeat Factor Length) leukocytes mean was 8.84 kpb, normal colonic mucosa 7.97 kpb, and tumoral mucosa 7.33 kpb (P < 0.001). In the 40 normal control patients, mean TRFL of colonic mucosa was 7.76 kpb, while in blood cells was 7.01 kpb (P < 0.001). We observed an inverse correlation between leukocytes TRFL and age (r(2)  = 0.17, P = 0.008). Mucosa TRFL correlates significantly with patient's age (r(2)  = 0.138, P = 0.018). TRFL of controls colonic mucosa correlates with TRFL of their blood cells (r(2)  = 0.354, P < 0.001).

Normal colonic mucosa and leukocytes in CCR patients presents telomere altered in respect to normal patients. Telomere length in normal leukocytes could be an initial marker for colorectal cancer.