BACKGROUND: p16(INK4a) methylation present in the tumors of colorectal cancer (CRC) patients can be detected in their serum using quantitative methylation-specific PCR (Q-MSP). To investigate the possibility that this technique could be applied to the monitoring for cancer recurrence in CRC patients, p16(INK4a) methylation in the serum of CRC patients during their follow-up period was evaluated. MATERIALS AND METHODS: Using Q-MSP on serum samples from 21 CRC patients undergoing surgery for primary CRC, the p16INK4a methylation score (p16(INK4a) MS) was evaluated one day before surgery and during the follow-up period. RESULTS: In the serum samples collected before primary resection, p16(INK4a) methylation was detected in 8 out of the 13 patients with same methylation in the tumor. The p16(INK4a) MS decreased within 2 weeks after surgery. Only two patients, who had the potential for recurrence, exhibited p16(INK4a) methylation in their serum. One month after surgery, in the patients with recurrence of tumor, a dramatic increase in p16(INK4a) MS was observed, while in the disease-free patients no methylation was seen continuously. CONCLUSION: p16(INK4a) MS could sensitively reflect the recurrence status and may be useful for identifying the presence of recurrence during the follow-up of CRC patients.
BACKGROUND:p16(INK4a) methylation present in the tumors of colorectal cancer (CRC) patients can be detected in their serum using quantitative methylation-specific PCR (Q-MSP). To investigate the possibility that this technique could be applied to the monitoring for cancer recurrence in CRC patients, p16(INK4a) methylation in the serum of CRC patients during their follow-up period was evaluated. MATERIALS AND METHODS: Using Q-MSP on serum samples from 21 CRC patients undergoing surgery for primary CRC, the p16INK4a methylation score (p16(INK4a) MS) was evaluated one day before surgery and during the follow-up period. RESULTS: In the serum samples collected before primary resection, p16(INK4a) methylation was detected in 8 out of the 13 patients with same methylation in the tumor. The p16(INK4a) MS decreased within 2 weeks after surgery. Only two patients, who had the potential for recurrence, exhibited p16(INK4a) methylation in their serum. One month after surgery, in the patients with recurrence of tumor, a dramatic increase in p16(INK4a) MS was observed, while in the disease-free patients no methylation was seen continuously. CONCLUSION:p16(INK4a) MS could sensitively reflect the recurrence status and may be useful for identifying the presence of recurrence during the follow-up of CRC patients.