A recent report revealed that phosphoinositide-3-kinase, catalytic, alpha (PIK3CA) gene is somatically mutated in several types of human cancer, suggesting the mutated PIK3CA gene as an oncogene in human cancers. However, because the previous report focused the mutational search primarily on colon cancers, the data on PIK3CA mutations in other types of human cancers have been largely unknown. Here, we performed mutational analysis of the PIK3CA gene by polymerase chain reaction-single-strand conformation polymorphism assay in 668 cases of common human cancers, including hepatocellular carcinomas, acute leukemias, gastric carcinomas, breast carcinomas, and non-small-cell lung cancers. We detected PIK3CA somatic mutations in 26 of 73 hepatocellular carcinomas (35.6%), 25 of 93 breast carcinomas (26.9%), 12 of 185 gastric carcinomas (6.5%), one of 88 acute leukemias (1.1%), and three of 229 non-small-cell lung cancers (1.3%). Some of the PIK3CA mutations were detected in the early lesions of breast cancer carcinoma, hepatocellular carcinoma, and gastric carcinomas, suggesting that PIK3CA mutation may occur independent of stage of the tumors. The high incidence and wide distribution of PIK3CA gene mutation in the common human cancers suggest that alterations of lipid kinase pathway by PIK3CA mutations contribute to the development of human cancers.

Sirtuins are nicotinamide adenine dinucleotide oxidized form (NAD 1 )-dependent deacetylases and function in cellular metabolism, stress resistance, and aging. For sirtuin7 (SIRT7), a role in ribosomal gene transcription is proposed, but its function in cancer has been unclear. In this study we show that SIRT7 expression was up-regulated in a large cohort of human hepatocellular carcinoma (HCC) patients. SIRT7 knockdown influenced the cell cycle and caused a significant increase of liver cancer cells to remain in the G 1 /S phase and to suppress growth. This treatment restored p21, induced Beclin-1, and repressed cyclin D1. In addition, sustained suppression of SIRT7 reduced the in vivo tumor growth rate in a mouse xenograft model. To explore mechanisms in SIRT7 regulation, microRNA (miRNA) profiling was carried out. This identified five significantly down-regulated miRNAs in HCC. Bioinformatics analysis of target sites and ectopic expression in HCC cells showed that miR-125a-5p and miR-125b suppressed SIRT7 and cyclin D1 expression and induced p21 WAF1/Cip1 -dependent G 1 cell cycle arrest. Furthermore, treatment of HCC cells with 5-aza-2 0 -deoxycytidine or ectopic expression of wildtype but not mutated p53 restored miR125a-5p and miR-125b expression and inhibited tumor cell growth, suggesting their regulation by promoter methylation and p53 activity. To show the clinical significance of these findings, mutations in the DNA binding domain of p53 and promoter methylation of miR125b were investigated. Four out of nine patients with induced SIRT7 carried mutations in the p53 gene and one patient showed hypermethylation of the miR-125b promoter region. Conclusion: Our findings suggest the oncogenic potential of SIRT7 in hepatocarcinogenesis. A regulatory loop is proposed whereby SIRT7 inhibits transcriptional activation of p21 WAF1/Cip1 by way of repression of miR-125a-5p and miR-125b. This makes SIRT7 a promising target in cancer therapy. (HEPATOLOGY 2013;57:1055-1067 S irtuins, also designated as class III histone deacetylases, are nicotinamide adenine dinucleotide oxidized form (NAD þ )-dependent deacetylases that target histone and nonhistone proteins and are implicated in the control of a wide range of biological processes such as apoptosis, stress responses, DNA repair, cell cycle, metabolism, and senescence. 1 The importance of sirtuins is demonstrated by their role in several major human pathologic conditions, including cancer, diabetes, cardiovascular disease, and neurodegenerative disease. 2 Mammals express seven sirtuins (denoted SIRT1-7) that have considerably different functions and catalytic activities. 3 The most closely related to yeast Sir2 and the best-characterized sirtuin, Abbreviations: 5-aza-dC, 5-aza-2 0 -deoxycytidine; CDKN1A, cyclin dependent kinase 1A;

Fas (Apo-1/CD95) is a cell-surface receptor involved in cell death signaling. The key role of the Fas system in negative growth regulation has been studied mostly within the immune system, and somatic mutations of Fas gene in cancer patients have been described solely in lymphoid-lineage malignancies. However, many nonlymphoid tumor cells have been found to be resistant to Fas-mediated apoptosis, which suggests that Fas mutations, one of the possible mechanisms for Fas-resistance, may be involved in the pathogenesis of non-lymphoid malignancies as well. In this study, we have analysed the entire coding region and all splice sites of the Fas gene for the detection of the gene mutations in 65 human nonsmall cell lung cancers by polymerase chain reaction, single strand conformation polymorphism and DNA sequencing. Overall, ®ve tumors (7.7%) were found to have the Fas mutations, which were all missense mutations. Four of the ®ve mutations identi®ed were located in the cytoplasmic region (death domain) known to be involved in the transduction of an apoptotic signal and one mutation was located in the transmembrane domain. This is the ®rst report on the Fas gene mutations in non-lymphoid malignancies, and the data presented here suggests that alterations of the Fas gene might lead to the loss of its apoptotic function and contribute to the pathogenesis of some human lung cancers.

ObjectivesTo assess the efficacy and safety of switching from the infliximab reference product (RP; Remicade) to its biosimilar CT-P13 (Remsima, Inflectra) or continuing CT-P13 in patients with rheumatoid arthritis (RA) for an additional six infusions.MethodsThis open-label extension study recruited patients with RA who had completed the 54-week, randomised, parallel-group study comparing CT-P13 with RP (PLANETRA; NCT01217086). CT-P13 (3 mg/kg) was administered intravenously every 8 weeks from weeks 62 to 102. All patients received concomitant methotrexate. Endpoints included American College of Rheumatology 20% (ACR20) response, ACR50, ACR70, immunogenicity and safety. Data were analysed for patients who received CT-P13 for 102 weeks (maintenance group) and for those who received RP for 54 weeks and then switched to CT-P13 (switch group).ResultsOverall, 302 of 455 patients who completed the PLANETRA study enrolled into the extension. Of these, 158 had received CT-P13 (maintenance group) and 144 RP (switch group). Response rates at week 102 for maintenance versus switch groups, respectively, were 71.7% vs 71.8% for ACR20, 48.0% vs 51.4% for ACR50 and 24.3% vs 26.1% for ACR70. The proportion of patients with antidrug antibodies was comparable between groups (week 102: 40.3% vs 44.8%, respectively). Treatment-emergent adverse events occurred in similar proportions of patients in the two groups during the extension study (53.5% and 53.8%, respectively).ConclusionsComparable efficacy and tolerability were observed in patients who switched from RP to its biosimilar CT-P13 for an additional year and in those who had long-term CT-P13 treatment for 2 years.Trial registration numberNCT01571219; Results.

The results suggest that genetic and epigenetic alteration of KLF6 may play a minor role in the development of HCC.

Accumulated evidence has established that aberrant regulation of histone deacetylases (HDACs) is one of the major causes of the development of human malignancies. Among different iso-enzymes of HDAC and sirtuins grouped as the HDAC super family, little is known as to how histone deacetylase 2 (HDAC2) causes carcinogenesis in solid tumors. Here, in order to investigate the possible role of HDAC2 in gastric carcinogenesis, we analyzed the expression of HDAC2 in 71 gastric adenocarcinomas by immunohistochemistry. Moderate to strong expression of HDAC2 was found in 44 (62%) out of a total of 71 tumors. The majority of positive tumors, which were detected in the nucleus but not in normal gastric epithelium, did not express HDAC2 or showed only weak positive staining. Interestingly, we also noted that HDAC2 expression appeared to be associated with tumor aggressiveness as HDAC2 expression was observed to be statistically significant in advanced gastric cancer (P=0.0023, Chi-square test) and in positive lymph node metastasis (P=0.0713, Chi-square test). Taken together, these results suggest that HDAC2 may play an important role in the aggressiveness of gastric cancer.

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Purpose: Recent reports revealed that the kinase domain of the ERBB2 gene is somatically mutated in lung adenocarcinoma, suggesting the mutated ERBB2 gene as an oncogene in human cancers. However, because previous reports focused the mutational search of ERBB2 primarily on lung cancers, the data on ERBB2 mutations in other types of human cancers have been largely unknown. Experimental Design: Here, we did a mutational analysis of the ERBB2 kinase domain by PCR single-strand conformational polymorphism assay in gastric, colorectal, and breast carcinoma tissues. Results: We detected the ERBB2 kinase domain mutations in 9 of 180 gastric carcinomas (5.0%), in 3 of 104 colorectal carcinomas (2.9%), and in 4 of 94 breast carcinomas (4.3%). All of the detected ERBB2 mutations except for one in-frame deletion mutation were missense mutations. Of the 16 ERBB2 mutations detected, 4 affected Val 777 in the exon 20 site, and 3 affected Leu 755 in the exon 19 site. We simultaneously analyzed the somatic mutations of EGFR, K-RAS, PIK3CA, and BRAF genes in the 16 samples with ERBB2 mutations, and found that all of the 3 colorectal carcinoma samples with ERBB2 mutations harbored K-RAS mutations. Conclusion:This study showed that in addition to lung adenocarcinomas, ERBB2 kinase domain mutation occurs in other common human cancers such as gastric, breast, and colorectal cancers, and suggested that alterations of ERBB2-mediated signaling pathway by ERBB2 mutations alone or together with K-RAS mutations may contribute to the development of human cancers.