Expression Of HLA-A, B MRNA In Peripheral Blood Mononuclear Cell In Colorectal Cancer Patients And Their Clinical Significances

Objective To study the expresssion of HLA-A mRNA and HLA-B mRNA in Peripheral Blood Mononuclear cell(PBMC) in colorectal cancer,the role of PBMC in the host celluar immunity,and their significances in monitoring the tumorigenesis and progression.Methods Gene-Specific primers were designed using Primer Premier 5.0 software,and then analyzed every sequence by BLAST to ensure that there were no significant sequence homologies with other genes.Beta-actin was used as a reference gene to normalize the results.The expression level of HLA-A mRNA,B mRNA in PBMC were determined by real-time PCR in 50 patients with colorectal cancer (cancer group),35 patients with benign colorectal lesion(benign group) and 42 healthy volunteers(control group).Compare the relative expression ratios of HLA-A, B mRNA in different TNM classification in the cancer group.The patients in cancer and benign groups were all confirmed by biopsy.The mean years of the three groups were similar to each other.The PCR data were analyzed by REST software(relative expression software tool) to get the relative expression ratio of HLA-A,B mRNA in the three groups.Chemoluminescence was used to detect the serum carcinoembryonic antigen(CEA),CA19-9 and CA242 in the three groups.The role of HLA-A,HLA-B mRNA in monitoring tumor were determined by receiver operating characteristic curve(ROC curve).Results1.The relative expression ratios of HLA-A and HLA-B mRNA in the three groupsThe relative expression ratio of PBMC HLA-A,B mRNA was 0.99±0.47,1.13±0.6 in healthy group;0.76±0.59,0.84±0.57 in benign colorectal lesion group and 0.38±0.31,0.39±0.35 in carcinoma group,respectively.The expression level of HLA-A,B mRNA in PBMC in colorectal carcinoma group was significantly lower than both benign colorectal lesion group and healthy control group(P＜0.001).2.The ratios in different TNM classification in the cancer groupThe expression ratio of HLA-A mRNA in colorectal cancer group in different TNM classification(Ⅰ～Ⅳ) was 0.48±0.32,0.64±0.75,0.56±0.41,0.61±0.34,respectively. The expression ratio of HLA-B in colorectal cancer group in different TNM classification(Ⅰ～Ⅳ) was 1.28±0.29,0.47±0.35,0.58±0.40,0.46±0.25,respectively. In colorectal carcinoma group,the relative expression ratio of HLA-A mRNA had no significant difference in different TNM classification(P＞0.05).HLA-B mRNA expression level in TNM classificationⅠwas significantly higher than that in TNM classificationⅡandⅣ(P＜0.05).Other comparisons of HLA-B mRNA between different TNM classifications had no significant difference.3.Preliminary evaluation of the PBMC HLA-A and HLA-B mRNA for monitoring colorectal cancerThe sensitivities of PBMC HLA-A and HLA-B mRNA for monitoring colorectal cancer were 84.4%and 70.2%,respectively.Conclusions1.We first study the expression of HLA-A mRNA and HLA-B mRNAin colorectal cancer,and found that the expression of HLA-A mRNA and HLA-B mRNA in colorectal cancer were significantly lower than both benign colorectal lesion group and healthy control group.2.Because of the significantly reduced expressions of HLA-A and HLA-B mRNA in PBMC in colorectal carcinoma,they could be developed to be a novel and available tumor marker to diagnose colorectal carcinoma,and may usher an era of tumor diagnosis.