Cheng Zhan

Pyruvate kinase M2 is highly correlated with the differentiation and the prognosis of esophageal squamous cell cancer.

Its frequently stated that the pyruvate kinase M2 (PKM2) and Warburg effect are important for cancer development by accumulating more raw materials for macromolecule biosynthesis. However, the correlation between PKM2 and cancer is poorly reported. Here, we investigated the PKM2 expression in esophageal squamous cell cancer (ESCC). We observed that the expression of PKM2 was much higher in ESCC than in control normal tissue, and it is highly associated with many clinical features and prognosis. Specially, we found that the expression of PKM2 was closely related to the differentiation state of ESCC, and we further confirmed this discovery in vitro. As a result, out data indicated that PKM2 might be a useful indicator for determining the survival of patients with ESCC. Considering previous researches on the link among PKM2, Warburg effect, and differentiation, our study inferred the direct roles of PKM2 and Warburg effect in the differentiation of cancer cells rather than only providing synthetic intermediates for the promotion of cancers progression.

Identification of reference genes for qRT-PCR in human lung squamous-cell carcinoma by RNA-Seq

Although the accuracy of quantitative real-time polymerase chain reaction (qRT-PCR) is highly dependent on the reliable reference genes, many commonly used reference genes are not stably expressed and as such are not suitable for quantification and normalization of qRT-PCR data. The aim of this study was to identify novel reliable reference genes in lung squamous-cell carcinoma. We used RNA sequencing (RNA-Seq) to survey the whole genome expression in 5 lung normal samples and 44 lung squamous-cell carcinoma samples. We evaluated the expression profiles of 15 commonly used reference genes and identified five additional candidate reference genes. To validate the RNA-Seq dataset, we used qRT-PCR to verify the expression levels of these 20 genes in a separate set of 100 pairs of normal lung tissue and lung squamous-cell carcinoma samples, and then analyzed these results using geNorm and NormFinder. With respect to 14 of the 15 common reference genes (B2M, GAPDH, GUSB, HMBS, HPRT1, IPO8, PGK1, POLR2A, PPIA, RPLP0, TBP, TFRC, UBC, and YWHAZ), the expression levels were either too low to be easily detected, or exhibited a high degree of variability either between lung normal and squamous-cell carcinoma samples, or even among samples of the same tissue type. In contrast, 1 of the 15 common reference genes (ACTB) and the 5 additional candidate reference genes (EEF1A1, FAU, RPS9, RPS11, and RPS14) were stably and constitutively expressed at high levels in all the samples tested. ACTB, EEF1A1, FAU, RPS9, RPS11, and RPS14 are ideal reference genes for qRT-PCR analysis of lung squamous-cell carcinoma, while 14 commonly used qRT-PCR reference genes are less appropriate in this context.

The Sweet Approach Is Still Worthwhile in Modern Esophagectomy

BACKGROUND The Ivor Lewis and Sweet approaches are the two most widely used open transthoracic esophagectomy techniques. We evaluated and compared the therapeutic efficacy of these two approaches to determine the appropriate method to treat middle or lower third esophageal carcinomas. METHODS We retrospectively reviewed patients who underwent esophagectomy with the Sweet (n=748) and Ivor Lewis (n=167) approaches at Zhongshan Hospital, Fudan University between January 2007 and December 2010. Patients with preoperatively identified superior mediastinal lymph node metastases, high-level lesions (above the carina), and benign tumors were excluded. Perioperative-related indicators and 5-year survival rates were compared between groups. RESULTS Compared with the Ivor Lewis approach, the Sweet approach has a shorter operative time (181±71 minutes versus 208±63 minutes; p<0.001), less blood loss (167±71 mL versus 179±87 mL; p=0.043), and a lower incidence of transfusion (8.7% versus 13.8%; p=0.044) and postoperative complications (12.3% versus 20.4%; p=0.002). The Ivor Lewis approach was more likely to result in wound infection (3.2% versus 7.8%; p=0.010) and delayed gastric emptying (1.7% versus 4.7%; p=0.046). There was no significant difference between groups with regard to the number of lymph nodes harvested or total number of patients with lymph node metastases. There was no significant difference in locoregional recurrence, distant recurrence, or 5-year survival between approaches. CONCLUSIONS The Sweet approach has many advantages for the treatment of middle or lower third esophageal carcinomas. It is a safe, effective, and worthwhile approach in modern thoracic surgery.

Identification of immunohistochemical markers for distinguishing lung adenocarcinoma from squamous cell carcinoma

BACKGROUND Immunohistochemical staining has been widely used in distinguishing lung adenocarcinoma (LUAD) from lung squamous cell carcinoma (LUSC), which is of vital importance for the diagnosis and treatment of lung cancer. Due to the lack of a comprehensive analysis of different lung cancer subtypes, there may still be undiscovered markers with higher diagnostic accuracy. METHODS Herein first, we systematically analyzed high-throughput data obtained from The Cancer Genome Atlas (TCGA) database. Combining differently expressed gene screening and receiver operating characteristic (ROC) curve analysis, we attempted to identify the genes which might be suitable as immunohistochemical markers in distinguishing LUAD from LUSC. Then we detected the expression of six of these genes (MLPH, TMC5, SFTA3, DSG3, DSC3 and CALML3) in lung cancer sections using immunohistochemical staining. RESULTS A number of genes were identified as candidate immunohistochemical markers with high sensitivity and specificity in distinguishing LUAD from LUSC. Then the staining results confirmed the potentials of the six genes (MLPH, TMC5, SFTA3, DSG3, DSC3 and CALML3) in distinguishing LUAD from LUSC, and their sensitivity and specificity were not less than many commonly used markers. CONCLUSIONS The results revealed that the six genes (MLPH, TMC5, SFTA3, DSG3, DSC3 and CALML3) might be suitable markers in distinguishing LUAD from LUSC, and also validated the feasibility of our methods for identification of candidate markers from high-throughput data.

Isoform Switch of Pyruvate Kinase M1 Indeed Occurs but Not to Pyruvate Kinase M2 in Human Tumorigenesis

Muscle type of pyruvate kinase (PKM) is one of the key mediators of the Warburg effect and tumor metabolism. Due to alternative splicing, there are at least 12 known isoforms of the PKM gene, of which PKM1 and PKM2 are two major isoforms with only a 23 amino acid sequenced difference but quite different characteristics and functions. It was previously thought the isoform switch from PKM1 to PKM2 resulted in high PKM2 expression in tumors, providing a great advantage to tumor cells. However, this traditional view was challenged by two recent studies; one study claimed that this isoform switch does not occur during the Warburg effect; the other study asserted that the isoform switch is tissue-specific. Here, we re-analyzed the RNA sequencing data of 25 types of human tumors from The Cancer Genome Atlas Data Portal, and confirmed that PKM2 was the major isoform in the tumors and was highly elevated in addition to the entire PKM gene. We further demonstrated that the expression level of PKM1 significantly declined even though there was substantially increased expression of the entire PKM gene. The proportion of PKM1 in total transcript variants also significantly declined in tumors but the proportion of PKM2 did not change accordingly. Therefore, we conclude that the isoform switch of PKM1 does indeed occur, but it switches to other isoforms rather than PKM2. Considering the change in the expression levels of PKM1, PKM2 and the entire PKM gene, we propose that the upregulation of PKM2 is primarily due to elevated transcriptional levels of the entire PKM gene, instead of the isoform switch.

Identification of reference miRNAs in human tumors by TCGA miRNA-seq data.

Although the accuracy of detecting the expression of miRNAs by quantitative real-time polymerase chain reaction (qRT-PCR) is highly dependent on reliable reference miRNAs, many commonly used reference miRNAs are not stably expressed and as such are not suitable for quantification and normalization of qRT-PCR data. To solve this problem, we analyzed the global expression profiles of thousands of samples in 14 types of common human tumors released by The Cancer Genome Atlas (TCGA), and identified the most stably and highly expressed miRNAs as candidate reference miRNAs in each type of tumor. We found that miR-361-5p and let-7i-5p were the most recommended candidate reference miRNAs in nine and eight types of tumors, respectively, followed by let-7a-5p, mir-28-5p and miR-99b-5p. Our results are of important value to those researchers focused on miRNA; however, these candidate reference miRNAs still need to be validated prior to their use in qRT-PCR studies.

Landscape of expression profiles in esophageal carcinoma by The Cancer Genome Atlas data.

In this study, we explored the gene and microRNA (miRNA) expressions profile of esophageal carcinoma. The expression data for messenger RNAs and miRNAs in normal and cancerous esophageal tissues were obtained from the Cancer Genome Atlas database and then the differentially expressed genes and miRNAs were identified. As a result, we identified 2962 genes and 45 miRNAs differentially expressed in esophageal carcinoma compared with normal esophageal tissues. Subsequently, the altered gene functions and signaling pathways were investigated using gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses, and these differentially expressed genes were significantly enriched in the cell cycle, cell migration, mitogen-activated protein kinase (MAPK) and toll-like receptor signaling pathway, and so on. Then the regulatory relationships between the differentially expressed miRNAs and genes were examined with Targetscan and Miranda, and the potential target sites of transcription factors (TFs) in the promoter regions of these miRNAs and genes were identified using the TRANSFAC database. Finally the TF-miRNA-gene network in esophageal cancer was established, summarizing the regulatory links among the TFs, differentially expressed miRNAs and differentially expressed genes. Factors such as core promoter-binding protein (CPBP), nuclear factor of activated T-cells 1 (NFAT-1), miR-30c-5p, were located in the central hub of this network, highlighting their vital roles in esophageal tumorigenesis. These findings may extend our understanding of the molecular mechanisms underlying esophageal carcinoma and promote new perspectives for prevention, diagnosis and treatment.

Lymph node metastasis in clinical stage IA peripheral lung cancer

OBJECTIVES To investigate lymph node metastasis especially the intrapulmonary node in clinical IA peripheral lung cancer patients to evaluate the indications for lung segmentectomy in lymph node level. MATERIALS AND METHODS Patients (n=292) with clinical stage IA peripheral lung cancer received radical lobectomy at our department between October 2013 and July 2014 were enrolled in our study. Lymph nodes were obtained during routine surgical procedures while segmental lymph nodes were dissected from the resected lobe for pathological examination. New classification for pulmonary adenocarcinoma with each histologic component was also analyzed. RESULTS The percentage of patients found to have no lymph node metastasis was 90.4% (264/292). Tumor size on computed tomography and tumor consistency were independent predictors for lymph node metastasis. Tumor with a dominant ground-glass opacity (GGO) component was a good predictor for lymph node metastasis (p<0.001). Metastasis was more common in larger tumors (p<0.001), but there was non-tumor bearing segment metastasis even in tumor less than 1cm. Patients with micropapillary or solid component were correlated with lymph node metastasis (p=0.001 and p=0.009, respectively). CONCLUSIONS The rate of metastasis to the lymph nodes is very low in clinical stage IA peripheral lung cancer patients. Patients with a dominant GGO component on CT might be the suitable candidates for lung segmentectomy because of almost no lymph node metastasis. Careful selection should be made for the patients with tumor size ≤2 cm who had metastasized nodes in non-tumor bearing segment when considering segmentectomy. If the resected tumor had micropapillary or solid component, the lobectomy might be considered.

Prognostic value of visceral pleural invasion in non-small cell lung cancer: A propensity score matching study based on the SEER registry

Visceral pleural invasion (VPI) is considered a poor prognostic factor in non‐small cell lung cancer (NSCLC). We aimed to analyze the effect of VPI on cancer‐specific survival, using propensity score matching (PSM) based on the Surveillance, Epidemiology, and End Results database.

MicroRNA-146a promote cell migration and invasion in human colorectal cancer via carboxypeptidase M/src-FAK pathway

Colorectal cancer (CRC) is one of the most common cancers worldwide, and microRNAs play important roles in CRC progression. This study aimed to investigate the roles of miR-146a-5p in human CRC and their molecular mechanisms. First, we found that miR-146a-5p was significantly upregulated in CRC tissues and promoted the migration of CRC cells. Then, we identified carboxypeptidase M (CPM) as a direct target of miR-146a-5p, and found that it inhibited the migration and invasion of CRC cells. Our results also showed that CPM expression was positively correlated with overall survival and negatively correlated with recurrence, lymph node invasion, and N stage. Furthermore, we demonstrated that both miR-146a-5p and CPM regulated Src and FAK expression, while the Src-FAK signaling pathway is widely known to be associated with the migration and invasion of multiple tumor cells. This study is the first to demonstrate the functional and mechanistic relationship of the miR-146a-5p/CPM/Src-FAK axis and its effect on the migration and invasion of CRC cells. Thus, miR-146a-5p represents potential targets for CRC diagnosis and therapy.