Telomere Shortening Occurs Early During Gastrocarcinogenesis

Objective:When telomeres are shortened to a critical length, they will initiate chromosomal instability (CIN) and may finally cause tumorigenesis. The purpose of the present study was to evaluate the shortened telomere as a potential biomarker for tumorigenesis in gastric carcinoma.Methods:The telomeres in matched cancer and adjacent noncancer mucosa samples from 86 gastric carcinoma patients were measured by real-time polymerase chain reaction (PCR). According to the International Union Against Cancer (UICC), tumor stages were classified into four groups:stageⅠ(n=23), stageⅡ(n=20), stageⅢ(n =23), and stageⅣ(n=20).Results:1. Telomere length decreased with aging in both adjacent noncancer mucosa and cancer tissue (r=-0.261 (P=0.008) and r=-0.27 (P=0.012), respectively).2. In males (n=58), the telomere lengths of adjacent noncancer mucosa and cancer tissue were 8.08±0.56 kb and 8.10±0.68 kb, respectively; in females (n=28), they were 8.31±0.78 kb and 8.39±1.02 kb, respectively. No significant difference between males and females was observed in the telomere length of adjacent noncancer mucosa or cancer tissue (P=0.189).3. Telomere length in cancer tissue and noncancer mucosa of all 86 patients were 4.8.16±0.64 (range,7.02kb-10.09kb) and 8.19±0.81 (range,6.54kb-11.19kb), respectively. There was no significant difference between the matched tissues.5. The telomere length of UICC stageⅠtumors was significantly shorter than the average telomere length in adjacent noncancer mucosa (P=0.023). Telomere length increased gradually with increasing UICC stage (P=0.032). The telomere length of UICC stageⅣtumors was significantly longer, as compared to that in noncancer mucosa (P=0.019) and stageⅠtumors (P=0.002).6. With increasing tumor invasion depth (pT), the telomere length in cancer tissue increased gradually (P=0.043);7. Telomeres of positive lymphatic invasion cancer tissue were significantly longer (8.32±0.85 kb; n=55) than telomeres of negative lymphatic invasion cancer tissue (7.93±0.58 kb; n=31; P=0.032).Conclusion:In summary, telomere length undergoes shortening in early-stage gastric carcinoma and lengthening in advanced gastric carcinoma. Additionally, telomere shortening may initiate the tumorigenesis of gastric carcinoma.