Mutations in KRAS exon 2, BRAF and PIK3CA are commonly present in colorectal cancer (CRC) worldwide, but few data about RAS mutations outside KRAS exon 2 are available for Chinese CRCs. We, therefore, determined the mutation frequencies and prognostic values of KRAS exon 2, 3 and 4, NRAS exon 2 and 3, PIK3CA exon 9 and 20, and BRAF exon 15 by PCR and direct sequencing in 353 CRC patients from two Chinese clinical centers. KRAS exon 2, BRAF, PIK3CA mutations were identified in 42.2%, 4.5%, 12.3% of the cases, respectively. We found “rare mutations” in RAS genes in nearly 14% of CRCs-i.e., in almost a quarter (24.0%) of KRAS exon 2 wild type CRCs, including 2.3% in KRAS exon 3, 8.2% in KRAS exon 4 and 3.4% in NRAS. Stage I-III patients with PIK3CA or NRAS mutations developed more distant metastases (3-year risk in PIK3CA mutated and wild type patients: 23.3% vs 11.5%, P = 0.03; multivariate Hazard ratio (HR) = 3.129, P = 0.003; 3-year risk in NRAS mutated and wild type patients: 40.0% vs 12.2%, P = 0.012; multivariate HR = 5.152, P = 0.003). Our data emphasizes the importance of these novel molecular features in CRCs.

Background: Next generation sequencing (NGS)-based multi-gene panel tests have been performed to predict the treatment response and prognosis in patients with colorectal cancer (CRC). Whether the multi-gene mutation results of formalin-fixed paraffin-embedded (FFPE) tissues are identical to those of fresh frozen tissues remains unknown.Methods: A 22-gene panel with 103 hotspots was used to detect mutations in paired fresh frozen tissue and FFPE tissue from 118 patients with CRC.Results: In our study, 117 patients (99.2%) had one or more variants, with 226 variants in FFPE tissue and 221 in fresh frozen tissue. Of the 129 variants identified in this study, 96 variants were present in both FFPE and fresh frozen tissues; 27 variants were found in FFPE tissues only; 6 variants were found only in fresh frozen tissues. The mutation results demonstrated >94.0% concordance in all variants, with Kappa coefficient >0.500 in 64.3% (83/129) of variants. At the gene level, concordance ranged from 73.8 to 100.0%, with Kappa coefficient >0.500 in 81.3% (13/16) of genes. Conclusions:The results of mutation analysis performed with a multi-gene panel and FFPE and fresh frozen tissue were highly concordant in patients with CRC, at both the variant and gene levels. There were, however, some important differences in mutation results between the two tissue types. Therefore, fresh frozen tissue should not routinely be replaced with FFPE tissue for mutation analysis with a multi-gene panel. Rather, FFPE tissue is a reasonable alternative for fresh frozen tissue when the latter is unavailable.

To compare protein expression levels, gene mutation and survival among Right-Sided Colon Cancer (RSCC), Left-Sided Colon Cancer (LSCC) and rectal cancer patients, 57 cases of RSCC, 87 LSCC and 145 rectal cancer patients were included retrospectively. Our results demonstrated significant differences existed among RSCC, LSCC and rectal cancer regarding tumor diameter, differentiation, invasion depth and TNM stage. No significant difference was identified in expression levels of MLH1, MSH2, MSH6, PMS2, β-Tubulin III, P53, Ki67 and TOPIIα, and gene mutation of KRAS and BRAF among three groups. Progression Free Survival (PFS) of RSCC was significantly lower than that of LRCC and rectal cancer. In univariate analyses, RSCC, preoperative chemoradiotherapy, poor differentiation, advanced TNM stage, elevated serum CEA and CA19-9 level, tumor deposit, perineural and vascular invasion were found to be predictive factors of shorter PFS. In multivariate analyses, only differentiation and TNM stages were found to be independent predictors of PFS. In conclusion, compared with LSCC and rectal cancer, RSCC has larger tumor size, poor differentiation, advanced TNM stage and shorter survival. The shorter survival in RSCC might be attributed to the advanced tumor stage caused by its inherent position feature of proximal colon rather than genetic difference.

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The objective was to evaluate the clinical value of preventative ileostomy following ultralow anterior rectal resection in decreasing the incidence of anastomotic leakage. For this purpose, 62 cases that had undergone ultralow anterior rectal resection during the period from June 2007 to June 2008 were included in this study. Preventative ileostomy was performed in 36 cases (group A) and 26 cases with no preventative ileostomy performed were included as controls (group B). The incidence rate of anastomotic leakage in both groups was compared. The results show that five cases in group A reported anastomotic leakage while no anastomotic leakage was reported in group B. Therefore, it was concluded that preventative ileostomy could effectively decrease the incidence of anastomotic leakage.

BackgroundIn most guidelines, upper rectal cancers (URC) are not recommended to take neoadjuvant or adjuvant radiation. However, the definitions of URC vary greatly. Five definitions had been commonly used to define URC: 1) >10 cm from the anal verge by MRI; 2) >12 cm from the anal verge by MRI; 3) >10 cm from the anal verge by colonoscopy; 4) >12 cm from the anal verge by colonoscopy; 5) above the anterior peritoneal reflection (APR). We hypothesized that the fifth definition is optimal to identify patients with rectal cancer to avoid adjuvant radiation.MethodsThe data of stage II/III rectal cancer patients who underwent radical surgery without preoperative chemoradiotherapy were retrospectively reviewed. The height of the APR was measured, and compared with the tumor height measured by digital rectal examination (DRE), MRI and colonoscopy. The five definitions were compared in terms of prediction of local recurrence, survival, and percentages of patients requiring radiation.ResultsA total of 576 patients were included, with the intraoperative location of 222 and 354 tumors being above and straddle/below the APR, respectively. The median distance of the APR from anal verge (height of APR) as measured by MRI was 8.7 (range: 4.5–14.3) cm. The height of APR positively correlated with body height (r=0.862, P<0.001). The accuracy of the MRI in determining the tumor location with respect to the APR was 92.1%. Rectal cancer above the APR had a significantly lower incidence of local recurrence than those straddle/below the APR (P=0.042). For those above the APR, there was no significant difference in local recurrence between the radiation and no-radiation group. Multivariate analyses showed that tumor location regarding APR was an independent risk factor for LRFS. Tumor height as measured by DRE, MRI and colonoscopy were not related with survival outcomes. Fewer rectal cancer patients required adjuvant radiation using the definition by the APR, compared with other four definitions based on a numerical tumor height measured by MRI and colonoscopy.ConclusionsThe definition of URC as rectal tumor above the APR, might be the optimal definition to select patients with stage II/III rectal cancer to avoid postoperative adjuvant radiation.

Based on structure and composition characteristics of engine oil, the new algorithm for its Infrared Spectrum (IR) Identification has been put forward. The Hit Quality Index and Related Hit Quality Index are widely used in Infrared Spectrum Identification recently. The two methods don’t take the importance of the variables into consideration and cannot distinguish the unobvious variation in IR spectra. Therefore the diversity weight factor was introduced into the new algorithm to promote its selectivity. The experimental results had shown that the new spectrum similarity evaluation index could distinguish the unobvious spectrum variations and to improve the infrared spectrum identification capability of engine oils.

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