title: Plasma Bmi1 mRNA as a potential prognostic biomarker for distant metastasis in colorectal cancer patients.
abstract: Bmi1 is overexpressed in gastrointestinal cancers, including colorectal cancer (CRC); however, its role as a non-invasive biomarker in CRC has not been established. The aim of this study was to compare the plasma Bmi1 mRNA levels prior to and following curative resection of the primary tumor in CRC patients and to determine their association with the clinicopathological parameters. The plasma Bmi1 mRNA level was measured by quantitative polymerase chain reaction and expressed as cycle threshold value. There was no significant difference between the overall pre- and postoperative plasma Bmi1 mRNA level (31.73±2.63 vs. 31.93±2.88, respectively; P=0.614) in 45 CRC patients. However, when grouped into non-metastatic and metastatic CRC patients, the postoperative Bmi1 transcript level was found to be significantly lower compared to the preoperative level in patients with non-metastatic CRC (32.13±2.677 31.44±2.764, respectively; P=0.041), whereas there was a trend towards a higher postoperative Bmi1 transcript level compared to the preoperative level in the metastatic counterpart (30.85±3.916 vs. 33.27±0.718, respectively; P=0.164). Furthermore, when the patients were categorized into two groups according to their plasma Bmi1 postoperative vs. preoperative level status, we observed that patients without a reduction in the postoperative plasma Bmi1 mRNA levels exhibited a significantly higher rate of distant metastasis following primary resection (P=0.017) and a significantly worse prognosis regarding disease-free survival (P=0.016) when compared to the reduced postoperative plasma Bmi1 level counterparts. In conclusion, plasma Bmi1 mRNA levels may serve as a non-invasive biomarker for monitoring occult metastasis and predicting the development of distant metastasis.
authors: The Chinese Foundation Secondary School, Hong Kong, SAR, P.R. China.
authors: Jason Chun-Sang
authors: JC
authors: Pun
authors: The Chinese Foundation Secondary School, Hong Kong, SAR, P.R. China.
authors: Joyce Yee-Jing
authors: JY
authors: Chan
authors: The Chinese Foundation Secondary School, Hong Kong, SAR, P.R. China.
authors: Bobby Ka-Ming
authors: BK
authors: Chun
authors: The Chinese Foundation Secondary School, Hong Kong, SAR, P.R. China.
authors: Ka-Wai
authors: KW
authors: Ng
authors: The Chinese Foundation Secondary School, Hong Kong, SAR, P.R. China.
authors: Samuel Yung-Kin
authors: SY
authors: Tsui
authors: Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, P.R. China.
authors: Timothy Ming-Hun
authors: TM
authors: Wan
authors: Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, P.R. China.
authors: Oswens
authors: O
authors: Lo
authors: Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, P.R. China.
authors: Jensen Tung-Chung
authors: JT
authors: Poon
authors: Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, P.R. China.
authors: Lui
authors: L
authors: Ng
authors: Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, P.R. China ; Centre for Cancer Research, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, SAR, P.R. China.
authors: Roberta
authors: R
authors: Pang
keywords: Bmi1; colorectal cancer; metastasis