Amplification of chromosome 21q22.3 harboring trefoil factor family genes in liver fluke related cholangiocarcinoma is associated with poor prognosis

Abstract

Aim: To determine allelic imbalance on chromosomal region 21q22-qter including trefoil factor family genes (TFF) in cholangiocarcinoma (CCA) patients and analyze the correlation between allelic imbalances and clinicopathological parameters.

Methods: Quantitative PCR amplification was performed on four microsatellite markers and trefoil factor family genes (TFF1, TFF2, and TFF3) using a standard curve and SYBR Green I dye method. The relative copy number was determined by DNA copy number of tested locus to reference locus. The relative copy number was interpreted as deletion or amplification by comparison with normal reference range. Associations between allelic imbalance and clinicopathological parameters of CCA patients were evaluated by chi(2)-tests. Kaplan-Meier method was used to analyze survival.

Results: The frequencies of amplification at D21S1890, D21S1893, and TFF3 were 32.5%, 30.0%, and 28.7%, respectively. Patients who had amplification at regions covering D21S1893, D21S1890, and TFF showed poor prognosis, whereas patients who had deletion showed favorable prognosis (mean: 51.7 wk vs 124.82 wk, P = 0.012). Multivariate Cox regression analysis revealed that amplification of D21S1893, D21S1890 and TFF, blood vessel invasion, and staging were associated with poor prognosis.

Conclusion: D21S1893-D21S1890 region may harbor candidate genes especially TFF and serine protease family, which might be involved in tumor invasion and metastasis contributing to poor survival. The amplification in this region may be used as a prognostic marker in the treatment of CCA patients.

Figure 1

Fine mapping of allelic imbalance on chromosomal region 21q22-qter. D21S1890 is located at telomeric end while D21S1253 is located toward centromeric end. There are two common amplification regions at D21S1890 and the region between D21S1893 and TFF3.

Figure 2

The association between survival time and allelic imbalance on loci D21S1893, D21S1890 and TFF was analyzed by Kaplan-Meier. The patients who had amplification at D21S1893, D21S1890 and TFF showed poor prognosis, whereas patients who had deletion at D21S1893, D21S1890 and TFF showed favorable prognosis.