Chong Lu

Expression levels of microRNA-375 in colorectal carcinoma

MicroRNAs are small, non-coding RNAs of endogenous origin. They have been increasingly shown to have altered expressions in many cancer types. The expression levels of miR-375 have not been comprehensively investigated in colorectal cancer. In this study, total RNA was extracted from 95 pairs of colorectal cancer tissues and non-tumor adjacent tissues, as well as from three colorectal cancer cell lines (HT-29, HCT-116 and SW-620). After polyadenylation and reverse transcription, we determined the expression levels of miR-375 by real-time PCR and calculated the difference in expression using the 2-∆∆Ct method. We assessed the correlation between the expression levels of miR-375 and clinicopathological characteristics of colorectal cancer. miR-375 expression was frequently downregulated in the colorectal cancer tissues compared to the non-tumor counterparts (p<0.001; paired t-test). Moreover, a significantly low expression of miR-375 was also found in the colorectal cancer cell lines (HT-29, p=0.002; HCT-116, p<0.001; SW-620, p=0.004; paired t-test). However, there were no significant correlations between the low expression of miR-375 and tumor size, histological grade, pT stage, pN stage and pTNM stage (all P>0.05, non-parametric test; Mann-Whitney U test between two groups and Kruskal-Wallis H test for three or more groups). miR-375 may be involved in the carcinogenesis of colorectal cancers and may be a potential biomarker for colorectal cancers.

A novel subclassification of pT2 gastric cancers according to the depth of muscularis propria invasion: superficial muscularis propria versus deep muscularis propria/subserosa.

Purpose:To propose a novel subclassification of pT2 gastric cancers according to the depth of muscularis propria (MP) invasion (superficial MP vs. deep MP/subserosa [SS]) and to investigate its impact in prognostic assessment. Summary Background Data:The major change in the sixth edition of the International Union Against Cancer (UICC)/American Joint Committee on Cancer (AJCC) TNM classification concerned the pT (primary tumor) category. Specifically, pT2 lesions were divided into pT2a (invading the MP) and pT2b (invading the SS) to discriminate these intramural locations. However, the value of the modification is still debated. Methods:One thousand two hundred fifty-six patients with pT2 cancers classified according to the UICC/AJCC pT staging system were reviewed. Among them, 214 (17.0%) were classified as invasion of the superficial MP (sMP) or inner circular muscle, 163 (13.0%) as invasion of the deep MP (dMP) or outer longitudinal muscle, and 879 (70.0%) as invasion of SS. Clinicopathologic features were compared between patients with sMP, dMP, and SS invasion. Overall survival rates were compared between the pT2a and pT2b stage cancers, according to the UICC/AJCC and the novel pT2 system. Two-step multivariate analysis was performed to identify the significantly important prognostic factors. Results:There was significant difference in most of the clinicopathologic features between sMP and SS cancers. Although, only 5 factors (tumor location, tumor size, Borrmann type, metastasis number, and metastasis ratio) were significantly different between dMP and SS cancers. In step 1 of the multivariate analysis, the UICC/AJCC pT2 system was an independent factor that correlated with prognosis, but was substituted by the novel pT2 system in step 2 of the multivariate analysis. With a certain metastasis ratio of lymph nodes, the novel pT2 system discriminated 2 subsets of patients with significantly different prognoses, whereas the UICC/AJCC pT2 system did not. Conclusions:The novel pT2 staging system, which was subclassified as sMP and dMP/SS cancers, had more potential to identify the different prognoses for patients with pT2 gastric cancers.

Positive association of heparanase expression with tumor invasion and lymphatic metastasis in gastric carcinoma

Tumor invasion and metastasis are the most common causes of death in gastric carcinoma. Human heparanase influences tumor invasiveness and angiogenesis. Analysis of its expression in gastric carcinoma has been hindered by our inability to procure pure cancer cells from heterogeneous tissue. In the present study, we analyzed heparanase expression in human primary and metastatic gastric carcinoma cells as well as in paired normal gastric epithelial cells by laser capture microdissection coupled with reverse transcription-polymerase chain reaction (RT-PCR). Tumor tissues, metastatic lymph nodes, and apparently uninvolved normal gastric tissues were collected from 30 patients who had undergone gastrectomy with radical lymph node dissection for gastric carcinoma without preoperative treatment. Bulk tissues and laser capture microdissected cell groups were separately subjected to RT-PCR analysis with heparanase-specific primers. For bulk tissues, heparanase-specific transcripts were detectable in all primary tumor tissues, metastatic lymph nodes, and almost all matching normal tissues. RT-PCR analysis after laser capture microdissection showed no detectable heparanase expression in matching normal epithelial cell groups. Of the laser capture microdissected primary gastric carcinoma cells, 47% (14/30) were heparanase positive. Expression was closely associated with greater tumor invasiveness, including Borrmann gross type and depth of wall infiltration. For metastatic cell groups dissected from lymph nodes, 95% showed clear heparanase expression. Furthermore, the extent of lymphatic spread was directly correlated to heparanase expression at the primary site. In conclusion, laser capture microdissection coupled with RT-PCR is a reliable approach for molecular analysis of heparanase expression in gastric carcinoma. Heparanase may facilitate invasion and metastasis of gastric carcinoma cells.

Differential β-catenin expression levels are associated with morphological features and prognosis of colorectal cancer

β-catenin, an epithelial-mesenchymal transition (EMT)-associated marker, is key in the progression of colorectal cancer (CRC). However, the prognostic significance of β-catenin expression in patients with CRC remains controversial. In the present study, the expression of β-catenin at the tumor invasive front and the tumor center was investigated, and the correlations amongst β-catenin differential expression patterns and the clinicopathological characteristics and prognosis of CRC patients were determined. In total, 181 patients that were diagnosed with CRC (as determined by histopathological evaluation) and subjected to surgical resection at the First Hospital of China Medical University between 2000 and 2001 were examined, and CRC specimens were obtained. Immunohistochemical (IHC) staining of β-catenin was performed for each specimen. The nuclear β-catenin expression levels were identified to be significantly lower in the tumor center than at the tumor invasive front (immunoreactivity score, 0.05±0.303 versus 2.18±3.917; P<0.001). The presence of nuclear β-catenin overexpression at the tumor invasive front was found to be correlated with the tumor, node, metastasis stage (P=0.020), lymph node metastasis (P=0.016) and histological differentiation (P=0.006). Survival analysis revealed that reduced membranous expression levels and increased nuclear expression levels of β-catenin were statistically significantly associated with poor survival times. Furthermore, differential β-catenin expression levels were associated with aggressive morphological features, EMT and a poor prognosis in CRC. Therefore, IHC analysis of β-catenin is considered to be a useful marker to predict the prognosis in patients with CRC.

Factors associated with peritoneal metastasis in non-serosa-invasive gastric cancer: a retrospective study of a prospectively-collected database

BackgroundPeritoneal dissemination is the most common type of recurrence in advanced gastric cancer. The main mechanism is thought to be via the exfoliation of free cancer cells (FCCs) from tumor in the gastric serosa. The frequency of recurrence thus increases once the tumor cells penetrate the serosa. However, this type of recurrence also occurs in patients without serosal invasion, though the mechanisms responsible for have not been fully established. We therefore investigated the factors associated with peritoneal dissemination in patients with non-serosa-invasive gastric cancer.MethodsA total of 685 patients with non-serosa-invasive gastric cancer who underwent curative resection with retrieval of more than 15 nodes were selected. The associations between clinicopathological features and peritoneal dissemination were analyzed. Among them, the tumor infiltrating growth pattern (INF) were classified into α, β and γ according to the Japanese Classification of Gastric Carcinoma (JCGC).ResultsThe overall incidence of peritoneal metastasis was 20% (137/685). Age, Borrmann type, differentiation, INF, nodal status and free cancer cells (FCCs) were correlated with peritoneal dissemination using univariate analysis. However, only INF, Borrmann type and TNM node stage were identified as independent correlated factors with peritoneal metastasis by multivariate analysis when FCCs were excluded, and these were also prognostic factors. Peritoneal dissemination was more common in patients with INFγ, Borrmann III/IV and N3 stage. Among patients without FCCs, nodal involvement or vessel invasion, only INF remained an independent associated factor according to multivariate analysis.ConclusionsTumor infiltrating growth pattern (INF), together with Borrmann type and TNM node stage, are important factors associated with peritoneal metastasis in non-serosa-invasive gastric cancer.

ILEI: a novel marker for epithelial–mesenchymal transition and poor prognosis in colorectal cancer

Accumulating evidence over the past decade has shown that abnormal activation of epithelial to mesenchymal transition (EMT) contributes to tumour progression and metastasis in colorectal cancer (CRC). In this study, we investigated the expression of interleukin‐like EMT inducer (ILEI) and EMT‐associated markers (E‐cadherin, vimentin) in CRC tissues and determined the correlations between ILEI expression and clinicopathological characteristics, prognosis and EMT in CRC.

Prognostic evaluation of platelet to lymphocyte ratio in patients with colorectal cancer

Growing evidence indicates that inflammation plays an important role in cancer progression and prognosis; however, the prognostic role of platelet to lymphocyte ratio (PLR) in colorectal cancer (CRC) is unknown. A cohort of 1845 CRC patients from the Department of Surgical Oncology at The First Hospital of China Medical University (CMU-SO) was retrospectively analyzed. Harrell’s concordance index (c-index) was used to determine the optimal cut-off value of PLR and evaluate its predictive ability. Our results from CMU-SO indicated that the overall survival (OS) rate was significantly lower in the high-PLR group compared with the low-PLR group (P = 0.001). A similar result was observed for the cancer-specific survival (CSS) rate between these two groups (P = 0.001). The multivariate analysis indicated that high PLR was an independent prognostic indicator of poor OS (hazard ratio [HR] = 1.356, 95% confidence interval [CI] = 1.117–1.647, P = 0.002) and CSS (HR = 1.364, 95% CI = 1.111–1.675, P = 0.003). In addition, the c-indexes of TNM staging combined with PLR were greater than those of TNM staging alone (OS: 0.768 vs. 0.732; CSS: 0.785 vs. 0.746). In conclusion, elevated PLR is a negative prognostic indicator of CRC and may serve as an additional index of the current TNM staging system for predicting CRC.