RT Journal Article SR Electronic T1 p16INK4a Methylation in Serum as a Follow-up Marker for Recurrence of Colorectal Cancer JF Anticancer Research JO Anticancer Res FD International Institute of Anticancer Research SP 1643 OP 1646 VO 31 IS 5 A1 NAKAYAMA, GORO A1 KODERA, YASUHIRO A1 OHASHI, NORIFUMI A1 KOIKE, MASAHIKO A1 FUJIWARA, MICHITAKA A1 NAKAO, AKIMASA YR 2011 UL http://ar.iiarjournals.org/content/31/5/1643.abstract AB Background: p16INK4a 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, p16INK4a 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 (p16INK4a MS) was evaluated one day before surgery and during the follow-up period. Results: In the serum samples collected before primary resection, p16INK4a methylation was detected in 8 out of the 13 patients with same methylation in the tumor. The p16INK4a MS decreased within 2 weeks after surgery. Only two patients, who had the potential for recurrence, exhibited p16INK4a methylation in their serum. One month after surgery, in the patients with recurrence of tumor, a dramatic increase in p16INK4a MS was observed, while in the disease-free patients no methylation was seen continuously. Conclusion: p16INK4a MS could sensitively reflect the recurrence status and may be useful for identifying the presence of recurrence during the follow-up of CRC patients.