No association between HER-2 gene polymorphism at codon 655 and a risk of bladder cancer

Epidermal Growth Factor Receptor and Human Epidermal Growth Factor Receptor 2 Gene Polymorphisms in Endometrial Cancer in a Japanese Population

Endometrial cancer is associated with both EGFR and HER2 receptor activation. The EGFR and HER2 genes could be disease susceptibility candidate genes for this cancer. This study was conducted to investigate a possible association between EGFR and HER2 gene polymorphisms and endometrial cancer and the influence of these polymorphisms on the clinical outcome of endometrial cancer patients in a Japanese population. The authors compare the genotype distributions and allele frequencies of the EGFR +2073 A/T and HER2 +655 A/G polymorphisms in 116 endometrial cancer patients and 213 controls using polymerase chain reaction-restriction fragment length polymorphism (RFLP) analysis. RFLP results were confirmed by direct DNA sequencing. Of the 116 patients, 76 (65.5%) could be followed up. Disease-free survival estimates were computed using the Kaplan-Meier method, and differences between survival periods were assessed using the log-rank test. No significant differences were observed in either genotype distributions or allele frequencies in the EGFR +2073 A/T and HER2 +655 A/G polymorphisms between endometrial cancer patients and controls. The stratification by histological types and staging failed to identify significant differences between endometrial cancer patients and controls. No statistical differences were noted between these polymorphisms and disease-free survival (Kaplan-Meier log-rank test P = .55 and .66, for the EGFR +2073 A/T and HER2 +655 A/G, respectively). These results suggest that the EGFR +2073 A/T and HER2 +655 A/G polymorphisms are not associated with endometrial cancer in a Japanese population. These conclusions are based on relatively small numbers and will require verification from additional independent studies.

Platelet Derived Growth Factor-B and Human Epidermal Growth Factor Receptor-2 Polymorphisms in Gall Bladder Cancer

Gall bladder cancer (GBC) is a gastro-intestinal cancer with high prevalence among north Indian women. Platelet derived growth factor-B (PDGFB) and human epidermal growth factor receptor-2 (HER2) may play roles in the etiology of GBC through the inflammation-hyperplasia-dysplasia-carcinoma pathway. To study the association of PDGFB and HER2 polymorphisms with risk of GBC, 200 cases and 300 controls were considered. PDGFB +286A>G and +1135A>C polymorphisms were investigated with an amplification refractory mutation system and the HER2 Ile655Val polymorphism by restriction fragment length polymorphism. Significant risk associations for PDGFB +286 GG (OR=5.25) and PDGFB +1135 CC (OR=3.19) genotypes were observed for GBC. Gender wise stratification revealed susceptibility for recessive models of PDGFB +1135A>C (OR=3.00) and HER2 Ile655Val (OR=2.52) polymorphisms among female GBC cases. GBC cases with gall stones were predisposed to homozygous +286 GG and +1135 CC genotypes. Significant risk associations were found for ACIle (OR=1.48), GAVal (OR=1.70), GAIle (OR=2.00) haplotypes with GBC cases and GCIle haplotype with female GBC cases (OR=10.37, P=<0.0001). Pair-wise linkage disequilibrium revealed negative associations among variant alleles. On multi-dimensional reduction analysis, a three factor model revealed significant gene-gene interaction for PDGFB +286A>G, PDGFB +1135A>C and HER2 Ile165Val SNPs with GBC. Protein-protein interaction showed significant association of PDGFB and HER2 with the epidermal growth factor receptor signaling pathway.

Impact of HER2 codon 655 polymorphism and expression of HER2 and HER3 in non small cell lung cancer patients

The aim of the study was to assess the expression and significance of HER2 and HER3, and Ile/Val single nucleotide polymorphism (SNP) of HER2 in lung cancer patients. Thirty seven cases of lung cancer were investigated immunohistochemically for HER2 and HER3 expression. PCR followed by restriction fragment length polymorphism (RFLP) was used to analyze the presence of HER-2 SNP at codon 655 in 20 samples. The results were compared with clinical and pathological parameters of investigated patients.We found that 100% of the cases were negative for HER2, 29.7% were with moderate or strong HER3 expression and 70.3% of the tumors-without or with low expression for HER3. Lymph node metastasis were found in 40% of HER3 positive cases (χ(2) = 4.752; p = 0.029). Moderately-differentiated tumors do not express neither of investigated markers (χ(2) = 6.719; p = 0.035). HER2 RFLP-PCR analysis showed genotype AG in five patients (25%) and the rest of 15 cases (75%) had АА (Ile/Ile) genotype. Patients with metastasis had genotype АА (Ile/Ile) in 80% and genotype AG (Ile/Val) in 20% (χ(2) = 2.857; p = 0.091).Our results indicate that SNP in HER2 codon 655 and investigation of HER2 and HER3 expression could be helpful to outline the prognosis for patients with lung adenocarcinoma.

Clinicopathologic significance of HER-2/neu protein expression and gene amplification in gastric carcinoma

AIM: To study the HER-2/neu protein expression and gene amplification in gastric carcinoma and their relation.

METHODS: One hundred and forty-five formalin-fixed and paraffin- embedded tumor tissue samples from Chinese gastric carcinoma patients were studied with immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) methods. Clinicopathologic data about all patients were collected.

RESULTS: The levels of HER-2 3+, HER-2 2+ and HER2 1+ were measurable in 6.9%, 8.3% and 17.2% of the samples, respectively. No HER-2 was stained in 67.6% of the samples. FISH showed that HER-2 gene was amplified in 18 samples, 10 HER-2 3+ samples, 5 HER-2 2+ samples, and 3 HER-2 1+ samples with IHC staining. HER-2 status was not correlated with the sex and age of patients, and tumor size, location or differentiation, but with the depth of invasion, TNM stage, lymph node and distant metastasis as well as histopathological classification of gastric cancer (P < 0.05).

CONCLUSION: All samples with IHC as HER-2 expression should be analyzed with FISH. Detection of HER-2 gene amplification can assess the malignant biological behaviors and prognosis of gastric cancer.

EGFR pathway polymorphisms and bladder cancer susceptibility and prognosis

The epidermal growth factor receptor (EGFR) pathway has recently been appreciated as a central mediator of tumorigenesis and an important drug target; however, the influence of genetic variation in this pathway on bladder cancer is not understood. Pathway activation leads to cell proliferation, angiogenesis and is antiapoptotic. We sought to test the hypothesis that bladder cancer susceptibility and survival are modified by inherited variations in the sequence of the EGFR and its pathway members. We tested associations using a population-based study of 857 bladder cancer cases and 1191 controls from New Hampshire. Multifactor dimensionality reduction software was used to predict gene-gene interactions. We detected an increased risk of bladder cancer associated with variant genotypes for the single nucleotide polymorphisms EGFR_03 [adjusted odds ratio (OR) 1.7 (95% confidence interval (CI) 1.0-2.8)] and EGFR_05 [adjusted OR 1.5 (95% CI 1.0-2.1)] compared with wild-type. EGFR variants experienced longer survival than those with wild-type alleles [e.g. adjusted hazard ratio EGFR_1808 0.3 (95% CI 0.1-0.9)]. In contrast, the variant form of the ligand, EGF_04, had worse survival [adjusted hazard ratio 1.5 (95% CI 1.0-2.3)] compared with wild-type. Our findings suggest modified bladder cancer risk and survival associated with genetic variation in the EGFR pathway. Understanding these genetic influences on increased bladder cancer susceptibility and survival may help in cancer prevention, drug development and choice of therapeutic regimen.

Investigation of HER-2 codon 655 single nucleotide polymorphism frequency and c-ErbB-2 protein expression alterations in gastric cancer patients

AIM: To investigate both whether the risk of gastric cancer is associated with the Ile/Val single nucleotide polymorphism (SNP) of human epidermal growth factor receptor-2 (HER-2) transmembrane domain-coding region at codon 655 and the suggested existence of HER-2 expression in gastric cancer cases in a Turkish patient group.

METHODS: Polymerase chain reaction (PCR) followed by restriction fragment length polymorphism (RFLP) strategy was used to analyze the presence of HER-2 SNP at codon 655. c-erbB-2 expression pattern was analyzed by immunohistochemistry. The results were compared between gastric carcinoma group and chronic gastritis group, as well as between clinicopathological parameters and carcinoma.

RESULTS: Results showed that Ile/Val genotype accounted for 20% within the Turkish gastric carcinoma group, and none in chronic gastritis group, and this genotyping was associated with stage IV gastric cancers (P = 0.04). Positive membranous HER-2 immunoreactivity, on the other hand, accounted for 24% within the Turkish gastric carcinoma group and none from chronic gastritis cases; further, it was correlated with intestinal type carcinomas (P = 0.007), and stage III-IV carcinomas (P = 0.004).

CONCLUSION: These observations imply that the tested HER-2 SNP may participate in the development and progression of gastric cancer. Thus, after confirming these results with large sample groups, HER-2 codon 655 SNP and/or c-erbB-2 overexpression may also be used as a poor prognostic indicator for gastric carcinomas.

Impact of IGF-I and CYP19 gene polymorphisms on the survival of patients with metastatic prostate cancer

PURPOSE

The prognosis of metastatic prostate cancer significantly differs among individuals. While various clinical and biochemical prognostic factors for survival have been suggested, the progression and response to treatment of those patients may also be defined by host genetic factors. In this study, we evaluated genetic polymorphisms as prognostic predictors of metastatic prostate cancer.

PATIENTS AND METHODS

One hundred eleven prostate cancer patients with bone metastasis at the diagnosis were enrolled in this study. Thirteen genetic polymorphisms were genotyped using polymerase chain reaction-restriction fragment length polymorphism or an automated sequencer with a genotyping software.

RESULTS

Among the polymorphisms, the long allele (over 18 [CA] repeats) of insulin-like growth factor-I (IGF-I) and the long allele (over seven [TTTA] repeats) of cytochrome P450 (CYP) 19 were significantly associated with a worse cancer-specific survival (P = .016 and .025 by logrank test, respectively). The presence of the long allele of either the IGF-I or CYP19 polymorphisms was an independent risk factor for death (P = .019 or .026, respectively). Furthermore, the presence of the long allele of both the IGF-I and CYP19 polymorphisms was a stronger predictor for survival (P = .001).

CONCLUSION

The prognosis of metastatic prostate cancer patients is suggested to be influenced by intrinsic genetic factors. The IGF-I (CA) repeat and CYP19 (TTTA) repeat polymorphisms may be novel predictors in prostate cancer patients with bone metastasis at the diagnosis.

HER-2 codon 655 polymorphism in cervical carcinogenesis

HER-2 codon 655 polymorphism together with human papillomavirus (HPV) types were examined in a total of 279 cervical smear samples. Forty-nine patients with high-grade squamous intraepithelial lesion had higher frequency of high-risk HPV than 167 patients with low-grade squamous intraepithelial lesion and 63 controls. There was no statistical difference in the frequencies of HER-2 Ile/Ile, Ile/Val, and Val/Val genotypes between squamous intraepithelial lesions (SILs) and controls. When the Ile/Ile genotype was compared to the Ile/Val + Val/Val genotypes, there was also no statistical difference in the genotype prevalence between SILs and controls either in 91 or 188 patients with or without high-risk HPV, respectively. These results suggest that the HER-2 polymorphism at codon 655 in cervical cell samples is unlikely to be associated with HPV status and the onset of cervical cancer in a Japanese population.

Her2 V655 genotype and breast cancer progression in Korean women

The amplification and overexpression of Her2 proto-oncogene have been found to be associated with the development and progression of human breast cancer. A polymorphic valine allele at codon 655 of the Her2 gene (Her2(V655)) was suggested by some authors to be a susceptible genetic factor for the development of breast cancer. The Her2 polymorphism at codon 655 was investigated in 304 Korean women including 177 patients with breast cancer. The association between Her2 genotype and Her2 protein overexpression was also examined in breast cancers by immunohistochemistry. Her2(V655) was not associated with a significant breast cancer risk (odds ratio (OR), 1.792; 95% confidence interval (CI), 0.459-6.991). The frequency of homozygous or heterozygous valine allele increased in stage 2 patients (OR, 1.67; 95% CI, 0.67-4.19), and patients in stages 3 and 4 (OR, 3.36; 95% CI, 0.85-13.42) compared to patients in stage 0. However, an association between the presence of the valine allele and the overexpression of Her2 protein could not be demonstrated. These results suggest that Her2 polymorphism at codon 655 is not associated with the development of breast cancer in Korean women. However, there is a possibility that the valine allele at codon 655 might be related to increased risk of breast cancer progression.

An evolutionary perspective on single-nucleotide polymorphism screening in molecular cancer epidemiology

Given that there are millions of single-nucleotide polymorphisms (SNPs) in the entire human genome, a major difficulty faced by scientists in planning costly population-based genotyping is to choose target SNPs that are most likely to affect phenotypic functions and ultimately contribute to disease development. Although it is widely accepted that sequences with important functionality tend to be less variable across species because of selective pressure, to what extent evolutionary conservation is mirrored by epidemiological outcome has never been demonstrated. In this study, we surveyed odds ratios detected for 46 SNPs in 39 different cancer-related genes from 166 molecular epidemiological studies. The conservation levels of amino acid that these SNPs affected were calculated as a tolerance index by comparing sequences from different species. Our results provide evidence of a significant relationship between the detected odds ratios associated with cancer risk and the conservation levels of the SNP-affected amino acids (P = 0.002; R(2) = 0.06). Tolerance indices were further calculated for 355 nonsynonymous SNPs identified in 90 human DNA repair genes, of which 103 caused amino acid changes in very conserved positions. Our findings support the concept that SNPs altering the conserved amino acids are more likely to be associated with cancer susceptibility. Using such a molecular evolutionary approach may hold great promise for prioritizing SNPs to be genotyped in future molecular epidemiological studies.