Purpose: Identification of novel biomarkers of cancer is important for improved diagnosis, prognosis, and therapeutic intervention. This study aimed to identify marker genes of colorectal cancer (CRC) by combining bioinformatics analysis of gene expression data and validation experiments using patient samples and to examine the potential connection between validated markers and the established oncogenes such as c-Myc and K-ras.Experimental Design: Publicly available data from GenBank and Oncomine were meta-analyzed leading to 34 candidate marker genes of CRC. Multiple case-matched normal and tumor tissues were examined by RT-PCR for differential expression, and 9 genes were validated as CRC biomarkers. Statistical analyses for correlation with major clinical parameters were carried out, and RNA interference was used to examine connection with major oncogenes.Results: We show with high confidence that 9 (ECT2, ETV4, DDX21, RAN, S100A11, RPS4X, HSPD1, CKS2, and C9orf140) of the 34 candidate genes are expressed at significantly elevated levels in CRC tissues compared to normal tissues. Furthermore, high-level expression of RPS4X was associated with nonmucinous cancer cell type and that of ECT2 with lack of lymphatic invasion while upregulation of CKS2 was correlated with early tumor stage and lack of family history of CRC. We also demonstrate that RPS4X and DDX21 are regulatory targets of c-Myc and ETV4 is downstream to K-ras signaling.Conclusions: We have identified multiple novel biomarkers of CRC. Further analyses of their function and connection to signaling pathways may reveal potential value of these biomarkers in diagnosis, prognosis, and treatment of CRC.

An increasing number of chromosomal aberrations is being identified in solid tumors providing novel biomarkers for various types of cancer and new insights into the mechanisms of carcinogenesis. We applied next generation sequencing technique to analyze the transcriptome of the non-small cell lung carcinoma (NSCLC) cell line H2228 and discovered a fusion transcript composed of multiple exons of ALK (anaplastic lymphoma receptor tyrosine kinase) and PTPN3 (protein tyrosine phosphatase, nonreceptor Type 3). Detailed analysis of the genomic structure revealed that a portion of genomic region encompassing Exons 10 and 11 of ALK has been translocated into the intronic region between Exons 2 and 3 of PTPN3. The key net result appears to be the null mutation of one allele of PTPN3, a gene with tumor suppressor activity. Consistently, ectopic expression of PTPN3 in NSCLC cell lines led to inhibition of colony formation. Our study confirms the utility of next generation sequencing as a tool for the discovery of somatic mutations and has led to the identification of a novel mutation in NSCLC that may be of diagnostic, prognostic, and therapeutic importance.