[Screening for EGFR mutations in lung cancer by a novel real-time PCR with double-loop probe and Sanger DNA sequencing].

OBJECTIVE: To map the frequency and types of EGFR gene mutations present in lung cancer tissues. To evaluate the clinical applicability of a novel real-time double-loop probe PCR of which the ADx-EGFR kit is based, and to compare its performance with traditional Sanger DNA sequencing in the detection of somatic mutations of tumor genes. METHODS: A total of 208 formalin-fixed paraffin-embedded (FFPE) tumor samples were tested. Genomic DNA of the tissue samples was extracted and purified, and subjected to both traditional PCR amplification, Sanger sequencing of EGFR gene in exon 18, 19, 20, 21, and ADx's EGFR mutation detection kit. The mutation rates for EGFR gene in exon 18, 19, 20, 21, as well as the frequency of each mutation detected by the two methods, were analyzed. RESULTS: The traditional Sanger DNA sequencing technique was successfully performed in 196 out of 208 (94.2%) lung cancer samples, and 22 samples (11.2%) showed EGFR gene mutations. ADx-EGFR kit was successfully used in the lung cancers of all of the 208 cases (100.0%), and 40 samples (19.2%) showed mutations. In the lung cancer samples analyzed, mutations were mainly detected in the exon 19 and exon 21 L858R point mutation, i.e. 4.8% (10/208) and 11.6% (23/208) of total mutations, respectively, and the remaining mutations were rare. CONCLUSIONS: The success rate of ADx-EGFR real-time PCR for formalin-fixed and paraffin-embedded tissues samples is significantly higher than that of Sanger sequencing (P < 0.01). There are significant differences between the two methods. ADx-EGFR real-time PCR shows a much higher successful detection rate and mutation rate of lung cancer tissues compared with that of Sanger sequencing. As a result, the real-time PCR with ADx-EGFR kit is proved to have a good clinical applicability and a strong advantage over the traditional Sanger DNA sequencing. It is an effective and reliable tool for clinical screening of somatic gene mutations in tumors.

The proteasome subunit PSMA7 located on the 20q13 amplicon is overexpressed and associated with liver metastasis in colorectal cancer.

The proteasome subunit PSMA7 located on the 20q13 amplicon was found to be differentially expressed in colorectal cancer by semiquantitative RT-PCR. PSMA7 mRNA was overexpressed in 37.5% (12/32) colorectal cancer tissues while it was either of a low level or not expressed in matched normal mucosa. The aim of this study was to examine the PSMA7 protein expression in 62 colorectal cancer primary sites, 34 lymph node metastatic sites and 13 liver metastatic sites by immunohistochemistry and clarify the correlations of this expression with the clinicopathological parameters. PSMA7 high expression was detected in 38.8% (24/62) colorectal cancer primary sites, 52.9% (18/34) lymph node metastatic sites and 100% (13/13) liver metastatic sites but not in the normal colorectal tissues. The PSMA7 high expression was significantly correlated with liver metastasis (P=0.028). Survival was significantly lower in patients with a PSMA7 high expression than in those with a PSMA7 low expression (P=0.0012). Moreover, in multivariate analysis, the PSMA7 expression demonstrated an independent prognostic factor (P=0.004, relative risk 5.057; 95% confidence interval, 1.682-15.201). These results indicated that PSMA7 may play an important role in colorectal cancer progression and provide a unique target site for the development of therapeutic drugs. The evaluation of PSMA7 expression in primary colorectal cancer at the time of surgery may be a valuable tool for defining patients with a high risk of developing liver metastasis.

[High expression of proteasome subunit PSMA7 in colorectal cancer is significantly correlated with liver metastasis].

OBJECTIVE: To investigate the correlation between the proteasome subunit PSMA7 expression in colorectal cancer and its role in liver metastasis. METHODS: To identify the PSMA7 protein expression in 62 primary site colorectal cancers, 34 lymph node metastatic sites and 13 liver metastatic sites by immunohistochemistry and clarify the correlation of its expression with the clinicopathological parameters. RESULTS: High expression of PSMA7 was detected in 38.7% (24/62) of primary site colorectal cancer, 52.9% (18/34) of lymph node metastatic sites and 100% (13/13) liver metastatic sites but not in the normal colorectal tissue. High expression of PSMA7 was significantly correlated with liver metastasis (P = 0.028). The survival rate was significantly lower in patients with high expression of PSMA7 than in those with low expression of PSMA7 (P = 0.0008). As well, in multivariate analysis, PSMA7 expression demonstrated to be an independent prognostic factor (P = 0.004, relative risk 5.057; 95% confidence interval, 1.682-15.201). CONCLUSION: PSMA7 may play an important role in the colorectal cancer progression. Evaluation of PSMA7 expression in primary colorectal cancer at the time of surgery might be a valuable test in defining patients with a high risk of developing liver metastasis.

Relationship between expression of CD105 and growth factors in malignant tumors of gastrointestinal tract and its significance.

AIM: Angiogenesis is an important step in the growth of solid malignant tumors. A number of angiogenic factors have been found such as transforming growth factor beta1 (TGF-beta1) and vascular endothelial growth factor (VEGF). However, the roles of TGF-beta1 and VEGF in gastrointestinal carcinogenesis are still unclear. This study was to investigate the expressions of TGF-beta1 and VEGF in gastrointestinal tract malignant tumors, as well as their association with microvessel density (MVD). At the same time, we also observed the localization of TGF-beta1 and its receptor CD105 in gastric malignant tumors. METHODS: The expressions of TGF-beta1 and CD105 were detected in 55 fresh specimens of gastric carcinoma and VEGF and CD105 in 44 fresh specimens of colorectal carcinoma by immunohistochemical staining (S-ABC). TGF-beta1 and CD105 in 55 gastric carcinoma tissues on the same slide were detected by using double-stain Immunohistochemistry (DS-ABC). RESULTS: Among the 55 cases of gastric carcinoma tissues, 30 were positive for TGF-beta1 (54.55%). The MVD of TGF-beta1 strong positive group (++ approximately +++ 23.22 +/- 5.8) was significantly higher than that of weak positive group (+17.56 +/- 7.2) and negative group (- 17.46 +/- 3.9) (q=4.5, q=5.3207, respectively, P<0.01). In the areas of high expression of TGF-beta1, MVD and the expression of CD105 were also high. Among the 44 cases of colonic carcinoma tissues, 26 were positive for VEGF (59.1%). The expressions of both VEGF and CD105 (MVD) were related with the depth of invasion (F=5.438, P<0.05; F=4.168, P=0.05), lymph node metastasis (F=10.311, P<0.01; F=20.282, P<0.01) and Dukes stage (F=6.196, P<0.01; F=10.274, P<0.01), but not with histological grade (F=0.487, P>0.05). There was a significant correlation between the expression of VEGF and CD105 (MVD) (r=0.720, P<0.01). CONCLUSION: Over-expression of TGF-beta1 and VEGF acts as stimulating factors of angiogenesis in gastrointestinal tumors. CD105, as a receptor of TGF-beta1, can regulate the biological effect of TGF-beta1 in tumor angiogenesis. MVD marked by CD105 is more suitable for detecting newborn blood vessels.

Genotype CC of rs1800947 in the C-reactive protein gene may increase susceptibility to colorectal cancer: a meta-analysis.

BACKGROUND: Single nucleotide polymorphisms of C-reactive protein (CRP) have been shown to be related to circulating CRP level, risk and prognosis in cancer patients. However, accumulating evidence of rs1800947 involvement in risk of cancer is inconsistent. Thus, a meta-analysis was performed to obtain a more precise relationship. MATERIALS AND METHODS: The pooled odds ratio (OR) and its 95% confidence interval were assessed in 10 eligible articles with 12 studies containing 5,601 cancer cases and 8,669 cancer-free controls. RESULTS: No significant association was observed overall and in subgroups in comparison of genotype GC vs GG (PH=0.847, OR=0.939, 95%CI=0.810-1.087), GC/CC vs GG (PH=0.941, OR=1.021, 95%CI=0.901-1.157) and allele C vs G (PH=0.933, OR=1.026, 95%CI=0.909-1.159). However, statistically significance was evident in comparison of genotype CC vs GG in cancer risk (PH=0.586, OR=2.854, 95%CI= 1.413-5.763), especially in colorectal cancer (PH=0.481, OR=4.527, 95%CI= 1.664- 12.315). CONCLUSIONS: Genotype CC of rs1800947 in the CRP gene is strongly associated with increased cancer risk, particularly in colorectal cancer.