Expression And Clinical Significance Of Pokemon In Renal Carcinoma

Background and objectives: Renal carcinoma is a common malignant tumororiginating from the urinary tubular epithelia of renal parenchyma. Among all urinarytumors, its morbidity rate ranks only after bladder cancer. Renal carcinoma will occur inany part of renal parenchyma and accounts for3%of adult patients of malignant tumors.The morbidity rate of renal cancer is still on the rise in recent years. Pokemon is amember of the transcription inhibitor family POK. The products encoded by Pokemonhave BTB domain and zinc finger, and thus Pokemon plays an important role in theoccurrence and development of tumors. Pokemon is involved not only in the regulationof cell cycle and cell apoptosis, but also acts as a central regulatory factor of theanti-oncogene--alterative reading frame (ARF). Studies show that pokemon isoverexpressed in human lung cancer, prostate cancer, colon cancer, lymphoma, andbladder cancer, and that pokemon can affect some important characteristics of tumorcells and may be necessary in the induction of cancers by other cancer genes. Theobjectives of this paper are to investigate the expressions of pokemon in renalcarcinoma at tissue and cell levels, and to provide a foundation for further study on theassociation of pokemon with the occurrence and development of renal carcinoma.Methods:(1) Human renal carcinoma tissues excised from clinical surgery werecollected as the experimental group (n=71), and normal kidney tissues>5cm from themargins of renal carcinoma tissues were selected as the control group (n=33). Thetissues were marked and immediately stored in a low-temperature refrigerator (-80℃).The protein and mRNA expressions of pokemon in renal cancer tissues and normalrenal tissues were detected and compared by using Western blot and RT-PCR. Themeasuring materials were statistically processed by randomized block analysis ofvariance on SPSS13.0and P<0.05was considered as statistical significance.(2) The patients were subdivided by sex, age, size of tumor, TNM staging, clinicalpathologic stages, occurrence of metastasis, and then compared between two groups to observe the expressions of pokemon in renal cancer tissues. Clinical pathologicalparameters were compared by using t-test and P<0.05was considered as statisticalsignificance.(3) Human renal carcinoma cell cancer cell line769-P and human kidney proximaltubular epithelial cell line HK-2were cultured conventionally. The protein and mRNAexpressions of pokemon in769-P and HK-2were detected by using Western blot andRT-PCR, and their correlations were analyzed. The measuring materials werestatistically processed by randomized block analysis of variance on SPSS13.0andP<0.05was considered as statistical significance.Results:(1) In the renal carcinoma tissues，Western blot and RT-PCR resultsshow that the protein and mRNA expression levels of pokemon in renal cancer tissuesare both significantly higher than in normal renal tissues.(2) In the specimens of renal carcinoma tissues, the protein and mRNA expressionlevels of pokemon in the low-differentiation group are significantly higher than in themedium-and high-differentiation groups. The protein and mRNA expression levels ofpokemon in the metastasis group are significantly higher than in the without-metastasisgroups Subgroup comparisons show that the protein and mRNA expression levels ofpokemon are not significantly related to sex, age, size of tumor or TNM staging.(3) In cell specimens, the protein and mRNA expression levels of pokemon aresignificantly higher in769-P than in HK-2. Spearman correlation analysis shows thatthe protein and mRNA expression levels of pokemon are in positive correlation in769-P,but not in HK-2(r=0.457).Conclusions:1. The protein and mRNA expression levels of Pokemon aresignificantly higher in renal cancer tissues and cells than in normal renal cells, whichindicates the association of Pokemon in the occurrence and development of renal cancer,as well as its potential significant role in the evolution of renal cancer.2. The expressionof Pokenmon is related to the clinical pathologic stages, and the occurrence ofmetastasis, but not significantly to sex, age, size of tumor or TNM staging.3. Ourresults are consistent with the fact that pokemon is overexpressed in several humantumors including lung cancer, prostate cancer, colon cancer, lymphoma and bladdercancer. Our results further prove that pokemon plays an important regulatory role inseveral tumors including renal carcinoma.