Objective: To investigate the methylation status of promoters of protocadherin-10 (PCDH10) and Ras-association domain family 1A (RASSF1A) genes in colorectal cancer (CRC), and to study its relationship with development and progress of CRC.
Methods: Tumor tissues were collected from 75 CRC patients who received surgical treatment in the Affiliated Hospital of Guizhou Medical University in the period from 2007 to 2010. Methylation-specific polymerase chain reaction (MSP) was applied to detect the methylation status of PCDH10 and RASSF1A gene promoters in CRC and adjacent normal colorectal mucosa. The relationship between methylation of PCDH10 and RASSF1A and clinicopathological features of CRC was analyzed using chi-squared test.
Results: The rate of PCDH10 methylation in CRC tissue was significantly higher than that in colorectal normal mucosa (58.7%(44/75)vs 22.7%(17/75), P<0.01). There was no significantly correlation between methylation of PCDH10 and patients' age, gender, tumor site, Dukes stage, and lymph node metastasis(all P>0.05). The rate of RASSF1A methylation in CRC tissue was significantly higher than that in colorectal normal mucosa (64.6%(42/65)vs 15.4%(10/65), P<0.01). There was no significantly correlation between methylation of RASSF1A and patients' age, gender, and tumor site (all P>0.05), but the patients in high Dukes stages and with lymph node metastasis had higher RASSF1A methylation rate(92.9%(26/28)vs 43.2%(16/37), 92.9%(26/28)vs 43.2%(16/37), both P<0.05).
Conclusions: CRC tissues demonstrate high level of methylation of PCDH10 and RASSF1A genes, which may play a crucial role in the pathogenesis of CRC. The aberrant hypermethylation of RASSF1A gene is observed in more advanced CRC, suggesting that the RASSF1A gene methylation may be related to progression of CRC.