Sporadic Gastric Cancer Patients Research Articles

Analysis of clinicopathological characteristics and prognosis of 91 patients with familial gastric cancer

To explore the clinicopathological characteristics and prognosis of familial gastric cancer(FGC) and to provide clinical evidence for rational treatment program. Clinicopathological data of 91 patients with FGC and 293 patients with sporadic gastric cancer(SGC) in our department from March 2003 to October 2007 were retrospectively analyzed and compared between the two groups. Tumors with a diameter of less than or equal to 5 cm were more common in FGC patients than SGC patients [65.9%(60/91) vs. 52.6%(154/293), P=0.025]. Proportion of FGC patients with poor differentiation was significantly higher as compared to SGC patients [68.1%(62/91) vs. 55.6%(163/293), P=0.034]. The 5-year overall survival rate in FGC patients was significantly lower than that in SGC patients(25.6% vs. 38.9%, P=0.001). Further stratified analysis revealed that the 5-year survival rates of T4 FGC and T4 SGC patients were 14.5% and 30.5% respectively, the 5-year survival rates of N3 FGC and N3 SGC patients were 10.4% and 17.3% respectively, and the differences were statistically significant(all P<0.05), while other T stage and N stage between the two groups were not significantly different(all P>0.05). Univarite analysis showed that tumor size, tumor location, pathological type, operation method, infiltration depth and lymph node metastasis were influencing factors of prognosis of FGC. Multivariate analysis showed that tumor size(HR=2.271), pathology types(HR=1.449), lymph node metastasis(HR=1.748) and the infiltration depth(HR=1.487) were independent risk factors affecting the prognosis of patients with FGC. Compared with SGC, FGC is associated with poor differentiation and poor prognosis.

Identification and Characterization of CDH1 Germline Variants in Sporadic Gastric Cancer Patients and in Individuals at Risk of Gastric Cancer

ObjectiveTo screen and characterize germline variants for E-cadherin (CDH1) in non-hereditary gastric cancer (GC) patients and in subjects at risk of GC.Methods59 GCs, 59 first degree relatives (FDRs) of GC, 20 autoimmune metaplastic atrophic gastritis (AMAGs) and 52 blood donors (BDs) were analyzed for CDH1 by direct sequencing, structural modelling and bioinformatics. Functional impact on splicing was assessed for intronic mutations. E-cadherin/β-catenin immunohistochemical staining and E-cadherin mRNA quantification using RT-PCR were performed.ResultsIn GCs, 4 missense variants (p.G274S; p.A298T; p.T470I; p.A592T), 1 mutation in the 5′UTR (−71C>G) and 1 mutation in the intronic IVS12 (c.1937-13T>C) region were found. First pathogenic effect of p.A298T mutation was predicted by protein 3D modelling. The novel p.G274S mutation showed a no clear functional significance. Moreover, first, intronic IVS12 (c.1937-13T>C) mutation was demonstrated to lead to an aberrant CDH1 transcript with exon 11 deletion. This mutation was found in 2 GCs and in 1 BD. In FDRs, we identified 4 variants: the polymorphic (p.A592T) and 3 mutations in untranslated regions with unidentified functional role except for the 5′UTR (−54G>C) that had been found to decrease CDH1 transcription. In AMAGs, we detected 2 alterations: 1 missense (p.A592T) and 1 novel variant (IVS1 (c.48+7C>T)) without effect on CDH1 splicing. Several silent and polymorphic substitutions were found in all the groups studied.ConclusionsOverall our study improves upon the current characterization of CDH1 mutations and their functional role in GC and in individuals at risk of GC. Mutations found in untranslated regions and data on splicing effects deserve a particular attention like associated with a reduced E-cadherin amount. The utility of CDH1 screening, in addition to the identification of other risk factors, could be useful for the early detection of GC in subjects at risk (i.e. FDRs and AMAGs), and warrants further study.

Molecular and Survival Differences between Familial and Sporadic Gastric Cancers

Mismatch repair (MMR) and germline E-cadherin (CDH1) mutations are two of the major pathways of carcinogenesis in familial gastric cancer (GC). A total of 260 sporadic and 66 familial GC patients were enrolled and molecular and survival differences were compared. Familial GC patients had earlier onset and were diagnosed at an earlier stage and had both a better 5-year overall survival rate and 3-year disease-free survival rate compared with sporadic GC patients. Only in diffuse type GC, the MSI-H phenotype and abnormal MMR protein expression were significantly higher in familial GC than in sporadic GC. In MSI-H GC, MLH1 promoter methylation was slightly higher in sporadic GC than familial GC (50% versus 23.1%), while the frequency of MMR gene mutation was slightly higher in familial GC than in sporadic GC (15.4% versus 3.1%). All of the patients with MMR gene mutation had diffuse type GC. Among familial GC patients with CDH1 mutation, most patients (72.3%) had diffuse type GC. In summary, for familial GC patients, we recommend screening of MSI status and CDH1 mutation especially for diffuse type GC. Because of the low incidence, mutation analysis of MMR gene might be considered in MSI-H familial GC with diffuse type only.

NovelCDH1germline mutations identified in Chinese gastric cancer patients

To give a comprehensive report of E-cadherin gene (CDH1) variations in a population at a high risk for gastric cancer (GC). The samples consisted of 178 men and 58 women with a mean age of 62.3 ± 9.4 years and an age range of 30-84 years. A total of 240 cancer-free controls were recruited (mean age of 61.8 ± 10.1 years, age range of 26-82 years). Samples were screened for CDH1 germline mutations by high-resolution melting analysis or directly sequencing. Luciferase reporter assay, RNA splicing assay and bioinformatic analysis were used to evaluate the effect of mutations. Four novel CDH1 sequence alterations were identified in GC patients including a G>T transition 49 bp before the start codon; a three-nucleotide deletion, c.44_46del TGC; one missense mutation, c.604G>A (V202I); and one variation in the intron, c.1320+7A>G. In addition, polymorphism frequencies were observed for CDH1-164delT, -161C>A, -73A>C, c.48+6C>T, c.48+62_48+63delinsCGTGCCCCAGCCC, c.894C>T (A298A), c.1224G>A (A408A), c.1888C>G (L630V), c.2076T>C (A692A), and c.2253C>T (N751N) which is similar to the data reported in http://www.ncbi.nlm.nih.gov/projects/SNP/. RNA splicing analysis suggested that the c.1320+7A>G and c.1224G>A variations did not affect exon splicing ability. Luciferase reporter assay demonstrated that the c.-49T variation might be helpful for E-cadherin transcription, though the increase in transcription activity is limited (only 33%). SIFT score and PolyPhen analysis both demonstrated that the L630V missense mutation probably damages protein function, while the V202I variant does not. This study reveals novel mutations in sporadic GC patients which had been poorly investigated for susceptibility genes.

Prognostic analysis of familial gastric cancer in Chinese population

The aim of this study was firstly to elucidate the prognosis of familial gastric cancer (FGC) in Chinese population. A total of 162 patients were recruited, including 81 patients with FGC and 81 patients with sporadic gastric cancer (SGC), who underwent gastrectomy between 1996 and 2007. Paraffin-embedded tumor specimens were obtained from tissue bank of Cancer Hospital, Fudan University. The expression of epidermal growth factor receptor (EGFR), P53, C-myc, and proliferating cell nuclear antigen (PCNA) were detected by immunohistochemical method. There were significant differences in tumor size, vessel invasion, EGFR, and P53 expression between FGC and SGC patients. The 5-year survival rates were 48% and 57% in FGC and SGC patients, respectively (P = 0.033). Subgroup analysis showed that the 5-year survival rates were worse in FGC patients with nerve invasion, high PCNA expression, negative expression of EGFR, and positive expression of P53 than those in SGC group. Multivariate analysis showed that AJCC stage, tumor size, and nerve invasion were independent prognostic factors in all patients. Furthermore, AJCC stage and P53 expression dramatically affected the prognosis of FGC patients. The prognosis of FGC patients might be worse than those of SGC patients. AJCC stage and P53 expression are independent prognostic factors in FGC patients.

Microsatellite Instability Is Associated with the Clinicopathologic Features of Gastric Cancer in Sporadic Gastric Cancer Patients

PurposeReplication error is an important mechanism in carcinogenesis. The microsatellite instability (MSI-H) of colorectal cancers is associated with the development of multiple cancers. The influence of MSI-H on the development of multiple gastric cancers in sporadic gastric cancer patients has not been defined. This study was performed to reveal the association between the clinicopathologic features and MSI in sporadic gastric cancers.Materials and MethodsBetween July 2004 and March 2009, the clinicopathologic characteristics, including MSI status, were evaluated in 128 consecutive patients with sporadic gastric cancers. None of the patients had hereditary non-polyposis colorectal cancer of familial gastric cancer. The markers that were recommended by the NCI to determine the MSI status for colorectal cancers were used.ResultsMSI-H cancers were found in 10.9% of the patients (14/128). Synchronous gastric cancers were shown in 4 patients (3.1%). Synchronous cancers were found in 2 of 14 patients with MSI-H gastric cancer (14.3%) and 2 of 114 patients with MSS gastric cancer (1.8%; P=0.059, Fisher's exact test). Among the patients with synchronous cancer 50% (2/4) had MSI-H cancer, but 9.7% of the patients (12/124) without synchronous cancer had MSI-H cancer. MSI-H (RR, 24.7; 95% CI, 1.5~398.9; P=0.024) was related with to synchronous gastric cancer, but age, gender, family history, histologic type, location, gross morphology, size, and stage were not related to synchronous gastric cancer.ConclusionsMSI is associated with the intestinal-type gastric cancer and the presence of multiple gastric cancers in patients with sporadic gastric cancer. Special attention to the presence of synchronous and the development of metachronous multiple cancer in patients with MSI-H gastric cancer is needed.

HMLH1 gene mutation in gastric cancer patients and their kindred

To study the status of hMLH1 gene point mutations of gastric cancer kindreds and gastric cancer patients from northern China, and to find out gene mutation status in the population susceptible to gastric cancer. Blood samples of 120 members from five gastric cancer families, 56 sporadic gastric cancer patients and control individuals were collected. After DNA extraction, the mutations of exon 8 and exon 12 of hMLH1 gene were investigated by PCR-SSCP-CE, followed by DNA sequencing. In the five kindreds, the mutation frequency was 25% (5/16) for the probands and 18% (19/104) for the non-cancerous members, which were significantly higher than the controls (P<0.01 chi2 = 7.71, P<0.01 chi2 = 8.65, respectively). In the sporadic gastric cancer, the mutation frequency was 7% (4/56), which was similar to that (5/100) in the healthy controls. The mutation point of exon 8 was at 219 codon of hMLH1 gene (A-G), resulting in a substitution of Ile-Val (ATC-GTC), whereas the mutation of exon 12 was at 384 codon of hMLH1 gene (T-A) resulting in a substitution of Asp-Val (GTT-GAT), which were the same as previously found in hereditary nonpolyposis colorectal carcinoma. The members of gastric cancer families from northern China may have similar genetic background of hMLH1 gene mutation as those of hereditary nonpolyposis colorectal carcinoma.

Microsatellite instability in gastric cancer is closely associated with hMLH1 hypermethylation at the proximal region of the promoter

Most sporadic gastric cancer with the microsatellite instability (MSI) phenotype is linked with hypermethylation (HM) of hMLH1. However, a part of gastric cancer with hMLH1 HM does not show MSI, suggesting a region-specific effect of hMLH1 promoter methylation on developing MSI. To test this possibility, we measured the methylation level in 3 distinct areas of hMLH1 promoter and compared them with MSI in 129 sporadic gastric cancer patients. Three areas of hMLH1 promoter, from distal toward proximal, were designated as hMLH1-A, hMLH1-B, and hMLH1-C, respectively. The methylation level was measured by fluorescence-based real-time methylation specific PCR. MSI status was tested using a panel of 5 microsatellite markers (BAT25, BAT26, D2S123, D5S346, and D17S250). Gastric cancers with no HM in hMLH1-A (n=105, 81.4%) also showed no HM in 2 other regions of hMLH1 promoter. On the other hand, the cancers with HM in hMLH1-A (n=24, 18.6%) showed various levels of methylation in 2 other regions. In most cases, the methylation value was the highest in hMLH1-A and the lowest in hMLH1-C. We found the MSI phenotype in 12 cancers (13%) of 92 tested cases and these cancers were all associated with HM in the region of hMLH1-C. A third of hypermethylated cancers in the hMLH1-A region did not show the MSI phenotype. The survival of the patients with HM in hMLH1-C was significantly better than that of patients without HM (P<0.05). These results suggest that HM in the proximal region of hMLH1 promoter, hMLH1-C in this study, plays a critical role in the progression of gastric cancer with MSI. The complete association between HM in hMLH1-C and MSI phenotype with gastric cancer provides an alternative diagnostic tool for detecting a favorable prognostic subgroup with MSI by using simple methylation analysis.

Genetic variations of the midkine (MK) gene in human sporadic colorectal and gastric cancers.

Midkine (MK), a retinoic acid responsible protein, is regulated during development and may play an important role in tumorigenesis. A search for genetic variations of the MK gene, located on chromosome 11q11.2 in humans, has not yet been conducted in cancers. To examine the entire coding region, as well as 4 regions of the promoter covering all functional motifs, 8 sets of intron-based and promoter region primers were designed. Using these primers, polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis of genomic DNA samples from 60 sporadic colorectal and 37 sporadic gastric cancer patients was carried out. This analysis, followed by DNA sequencing, revealed a heterozygous g/t polymorphism at the 62nd base on intron 3 in five colorectal tumors (8.3%) and one gastric tumor (2.7%). In the promoter region, a heterozygous CTT deletion, creating a (CTTTT)2 repeat, in one colorectal cancer sample (1.67%) and a heterozygous 2-bp deletion in the G7 tract in another colorectal cancer patient were detected. A/G and A/A alleles were also detected at nt. -1741 in 36 (97.3%) and one (2.7%) gastric cancer samples, respectively. The A/G alleles were observed in all colorectal cancer patients (100%). All variations observed in the promoter region showed polymorphism. These results suggest that in sporadic colorectal and gastric cancers some gene alterations are present in the MK promoter region, but alterations in the coding region are rare.

Absence of mutatins in the analysis of coding sequences of the entire transforming growth factor beta type II receptor gene in sporadic humangastric cancer using genomic DNA and intron primers.

Mutations in the transforming growth factor beta type II receptor (TGFbetaRII) gene have been detected in several human cancers that represent the phenotype of genomic instability. To establish a basis for diagnosis of cancer patients, we previously determined the exon-intron organization of the TGFbetaRII gene. The results indicated that TGFbetaRII protein is encoded by 567 codons in 7 exons. In this study, we further determined the nucleotide sequences surrounding these 7 exons and designed 8 sets of intron-based primers to examine the entire coding region of the TGFbetaRII gene. By using these primers, we screened for mutations of the TGFbetaRII gene in DNAs of 32 sporadic gastric cancer patients in whom one case showed MI+ (3.1%) at two loci. We found no mutations, and these data support other recent evidence that TGFbetaRII mutations rarely occur except in colon and gastric tumors with MI.