Her2 V655 genotype and breast cancer progression in Korean women

BCL-2 (-938C>A), BAX (-248G>A), and HER2 Ile655Val Polymorphisms and Breast Cancer Risk in Indian Population

Breast cancer is the most common carcinoma in women worldwide. The present case-control study was aimed to examine the association of BCL-2 (-938C> A), BAX (-248G > A), and HER2 (I655V i.e. A > G) polymorphisms with breast cancer risk in Indian population. This study enrolled 117 breast cancer cases and 104 controls. BCL-2 (-938C > A), BAX (-248G > A), and HER2 Ile655Val polymorphisms were screened by PCR-RFLP method. There was no significance difference in the allelic and genotype frequency of the BCL-2 (-938C > A) and BAX (-248G > A) polymorphisms between cases and controls. In relation to HER2 Ile655Val polymorphism, the statistical analysis of observed genotypic frequencies showed significant association (p-0.0059). Compared to Ile/Ile (A/A) genotype, frequency of Ile/Val (A/G) genotype was significantly higher among cases than in control group and observed to increase the breast cancer risk (OR, 2.43; 95%CI, 1.32-4.46; p-0.004). The frequency of Val (G) allele was significantly higher in cases as compared to controls (6.83% vs 2.88%, resp.). Compared to Ile (A) allele, significant increase in the risk of breast cancer was observed with Val (G) allele (OR, 2.21; 95% CI, 1.35-3.63; p-0.0016). We observed significant association between HER2 Ile655Val polymorphism and breast cancer risk under the dominant (OR = 2.52; 95% CI: 1.41-4.51; p-0.001) and codominant (OR, 2.24; 95% CI: 1.23-4.09; p-0.008) model. In our study, BCL-2 (-938C > A) and BAX (-248G > A) polymorphism were not found to be associated with breast cancer risk. This present study for the first time shows significant association of HER2 Ile655Val polymorphism with risk of breast cancer in Indian population. Therefore, we suggest that each population need to evaluate its own genetic profile for breast cancer risk that may be helpful for better understanding the racial and geographic differences reported for breast cancer incidence and mortality.

HER2Ile655Val Single Nucleotide Polymorphism Associated with Early-Onset Breast Cancer Susceptibility: A Systematic Review and Meta-Analysis

Background:

Human epidermal growth factor receptor 2 (HER2) plays an important role in the development and progression of breast cancer. To understand the precise association, this meta-analysis was conducted to estimate the association between HER2^Ile655Val single nucleotide polymorphism (SNP) and susceptibility to early-onset breast cancer.

Methods:

A comprehensive database retrieval from PubMed, Embase, Web of Science and Google Scholar was pooled to investigate links between the HER2^Ile655Val SNP and risk of breast cancer. Adjusted odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to appraise the association under the additive model (Ile vs. Val), dominant model (Val/Val + Ile/Val vs. Ile/Ile), and recessive model (Val/Val vs. Ile/Val + Ile/Ile).

Results:

Seventeen relevant studies with 11,749 cases and 8,105 controls were finally included. We found that HER2^Ile655Val SNP is associated with an increased risk of breast cancer in an additive and dominant model. In the subgroup analysis with age stratification, a significant association between the HER2 codon 655 SNP and the risk of breast cancer was found in young women in an additive, dominant, and recessive model; conversely, no significant associations were indicated in older women. In the breast cancer subgroup, HER2^Ile655Val SNP was significantly associated with younger age women with breast cancer in the dominant model. In contrast, no association between the HER2 codon 655 SNP and age was found in control populations.

Conclusion:

Our findings suggest that the Val allele in HER2 codon 655 SNP is strongly associated with breast cancer susceptibility in the young female population and is also significantly associated with younger age in women with breast cancer. HER2^Ile655Val SNP might be a susceptibility factor that favours early-onset breast cancer.

Her2 Ile655Val polymorphism and its association with breast cancer risk: an updated meta-analysis of case-control studies

Breast cancer (BC) is one of the most common types of cancer in women worldwide. Several factors including genetic and environmental have been linked with susceptibility to development of BC. Her2 is a transmembrane protein with tyrosine kinase activity, overexpressed in several cancers including BC. Various studies in different populations have shown association of Her2 variants with susceptibility to BC, however these results were inconsistent, inconclusive and controversial. To obtain a common conclusive finding, we performed meta-analysis of 35 case-control studies reported earlier including 19, 220 cases and 22, 306 controls. We observed significant association of Her2^Ile655^Val polymorphism with susceptibility to development of breast cancer (Overall allele Val vs Ile: OR = 1.130, 95% CI = 1.051–1.216, p = 0.001; Ile-Val vs Ile-Ile: OR = 1.100, 95% CI = 1.016–1.192, p = 0.019; Val-Val+Ile-Val vs Ile-Ile: OR = 1.127, 95% CI = 1.038–1.223, p = 0.004). Subgroup analysis indicated a significant association with susceptibility to breast cancer in African and Asian populations. However, such association was not observed in other ethnic groups. Our findings suggested that Her2^Ile655^Val polymorphism is associated with breast cancer risk in overall, Asian and African populations, and can be used as diagnostic marker for BC.

Dataset reporting detection of breast cancer-related HER2I655V polymorphism using allele-specific polymerase chain reaction

The dataset presented in this article is related to the research article entitled “Detection of HER2 Gene Polymorphism in Breast Cancer: PCR Optimization Study” (B.R. Budiarto, Desriani, 2016) [1] with some modification in primers used and in PCR optimization strategy to eliminate false-positive result that may occur in HER2^I655V polymorphism detection. Combining a new set of primers with PCR gradient, The allele-specific PCR well performs to detect all type of breast cancer-originated HER2^I655V genotypes. The validation of this method was done using Sanger DNA sequencing, offering an alternative tool for HER2^I655V polymorphism detection in another type of 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.

Updated meta-analysis on HER2 polymorphisms and risk of breast cancer: evidence from 32 studies

BACKGROUND

Several studies have been performed to investigate the association of the HER2 Ile655Val polymorphism and breast cancer risk. However, the results were inconsistent. To understand the precise relationship, a meta-analysis was here conducted.

MATERIALS AND METHODS

A search of PubMed conducted to investigate links between the HER2 Ile655Val polymorphism and breast cancer, identified a total of 32 studies, of which 29, including 14,926 cases and 15,768 controls, with odds ratios (ORs) with 95% confidence intervals were used to assess any association.

RESULTS

In the overall analysis, the HER2 Ile655Val polymorphism was associated with breast cancer in an additive genetic model (OR=1.136, 95% CI 1.043-1.239, p=0.004) and in a dominant genetic (OR=1.118, 95% CI 1.020-1.227, p=0.018), while no association was found in a recessive genetic model. On subgroup analysis, an association with breast cancer was noted in the additive genetic model (OR=1.111, 95% CI: 1.004-1.230, p=0.042) for the Caucasian subgroup. No significant associations were observed in Asians and Africans in any of the genetic models.

CONCLUSIONS

In summary, our meta-analysis findings suggest that the HER2 Ile655Val polymorphism is marginally associated with breast cancer susceptibility in worldwide populations with additive and dominant models, but not a recessive model.

Lack of association between HER2 codon 655 polymorphism and breast cancer susceptibility: meta-analysis of 22 studies involving 19,341 subjects

Epidemiological studies have investigated the association between HER2 codon 655 polymorphism and breast cancer susceptibility. However, the results are still inconclusive. To obtain a more precise estimation of the relationship, this meta-analysis was performed. A total of 22 studies including 9,209 cases and 10,132 controls were collected. The strength of association between HER2 codon 655 polymorphism and breast cancer susceptibility was assessed by calculating crude ORs with 95% CIs. When all the 22 studies were pooled into the meta-analysis, there was no evidence for significant association between HER2 codon 655 polymorphism and breast cancer susceptibility (for Val/Ile vs. Ile/Ile: OR = 1.069, 95% CI = 0.976-1.172; for Val/Val vs. Ile/Ile: OR = 1.191, 95% CI = 0.922-1.538; for dominant model: OR = 1.093, 95% CI = 0.991-1.206; for recessive model: OR = 1.141, 95% CI = 0.902-1.444). In the subgroup analysis by the source of controls and ethnicity, no significant increased risk was found in all genetic models. However, the current results indicated the modest association between the HER2 Ile655Val polymorphism and Asian population (Val/Ile vs. Ile/Ile: OR = 1.207, CI = 1.006-1.450). In summary, the meta-analysis suggests that HER2 codon 655 polymorphism is not associated with the increased breast cancer risk.

HER2 polymorphisms and breast cancer in Tunisian women

HER2 has been thought to play a critical role in both breast cancer development and progression. Any functional polymorphisms can potentially affect breast cancer risk as well as cancer phenotype and outcome. In our study, we analyzed three polymorphisms in the HER2 gene: the single-nucleotide polymorphism (SNP) HER2 Ile(655)Val as well as another SNP (rs903506) close to it and a new screened dinucleotide repeat H(AC)I4 in intron 4, in a sample of 148 cases and 290 controls from the Tunisian population and investigated their association with breast cancer risk. For the HER2 Ile(655)Val, we found similar allele frequencies between cases and controls (frequency of I allele was 0.92 and 0.91, respectively). The same was observed for the noncoding SNP (rs903506). These two SNPs also showed no association with any clinical parameters, except the association of HER2 Ile(655)Val with tumor size (p = 0.002). But, a significant association was found between the short tandem repeat (STR) [H(AC)I4] and breast cancer risk at both genotypic and allelic levels (p = 0.0004 and p = 0.0001, respectively). Multivariate analysis with binary logistic regression of disease status on genotypes of the three polymorphisms confirmed the association of STR with breast cancer risk (p = 0.016). Therefore, this STR seems to be a promising biomarker in breast cancer and deserves further investigation.

The genetic polymorphisms of HER-2 and the risk of lung cancer in a Korean population

Background

Human Epidermal Growth Factor Receptor 2 (HER-2; also known as erbB-2 or neu), a proto-oncogene of the receptor tyrosine kinase superfamily, has been associated with carcinogenesis and prognosis of human cancers, acting as a binding partner of other epidermal growth factor receptor (EGFR) family in the activation of EGFR signaling. Amplification of the HER-2 gene has been reported in lung cancer, where it has been associated with poor prognosis. In this study, we investigated whether the four polymorphisms (-3444C>T, -1985 G>T, I655A A>G and P1170A C>G) of the HER-2 gene are associated with the risk of lung cancer in Korean populations.

Methods

The frequencies of 4 polymorphisms of the HER-2 gene were examined by the polymerase chain reaction-restriction fragment length polymorphism or the single-nucleotide polymorphism-identification technology assay in the 407 lung cancer patients and 407 healthy controls.

Results

The frequencies of the 4 polymorphisms were not significantly different between patient and control groups in overall subjects. However, in the subgroup analysis, the 3 single nucleotide polymorphisms (-3444C>T, -1985G>T and P1170A C>G) showed statistically significant differences in the subgroups of females, non-smokers, and non-drinkers (p < 0.05). Additionally, we found the association between the risk of lung cancer and the polymorphisms of HER-2 gene in non-smoker subgroups with adenocarcinoma (p < 0.05).

Conclusion

Our results suggest that the polymorphisms of the HER-2 gene are associated with an increased susceptibility to lung cancer in females, non-smokers and non-drinkers subgroups in the Korean population.

Focus on ERBB2

The ERBB2 (HER2) gene codes for a tyrosine kinase receptor that activates pathways involved in cell division, differentiation and apoptosis. Gene amplification, and as a result protein overexpression, are commonly seen in breast tumors and correlate with poor prognosis. The overexpressed protein is the target of trastuzumab, a monoclonal antibody routinely used in clinical practice. A new tyrosine kinase inhibitor, lapatinib, is already an alternative in women progressing despite treatment with trastuzumab. Using comprehensive tagging approaches, highly-powered association studies concluded that ERBB2 was unlikely to be a breast cancer predisposition gene. ERBB2 pharmacogenomics are of little relevance at present, since we have no knowledge of polymorphisms in the gene that could affect the binding, efficacy or tolerability of trastuzumab or lapatinib. There is minor contribution from hepatic cytochrome CYP2C19 to the metabolism of lapatinib, whereas in vitro studies have shown the drug to be a substrate for the transporter P-glycoprotein. If, and how, the pharmacokinetics of lapatinib would be altered in individuals carrying polymorphisms in CYP2C19 or ABCB1 – the gene that codes for the P-glycoprotein – is yet to be determined.

Role of the HER2 [Ile655Val] genetic polymorphism in tumorogenesis and in the risk of trastuzumab-related cardiotoxicity

BACKGROUND

To examine the impact of a frequent her2 gene polymorphism (Ile655Val) on tumor growth and on the pharmacodynamics of treatment by trastuzumab.

PATIENTS AND METHODS

Experimental study: The growth characteristics of cells expressing the Ile or Val isoform were examined in vitro and after injection into nude mice. The effect of trastuzumab was determined in both experimental models. Clinical study: 61 patients with advanced breast cancers and treated by trastuzumab were genotyped for HER2 by PCR-RFLP. The influence of HER2 genotype on the trastuzumab treatment was examined.

RESULTS

Experimental study: HER2-expressing cells acquired the characteristics of tumor cells. The Val isoform-expressing cells showed the highest growth capacity and developed aggressive tumors sensitive to trastuzumab. Clinical study: There was no link between tumor response or survival and HER2 genotype. All cases of treatment-related cardiotoxicity were found in the Ile/Val group and there was no cardiac toxicity in the Val/Val and Ile/Ile patients.

CONCLUSIONS

This study establishes a clear-cut difference between the two HER2 isoforms regarding their tumorogenic potential with an advantage for the Val/HER2 isoform. In breast cancer patients treated with trastuzumab, the presence of a Val allele may constitute a risk factor for cardiac toxicity.

Allelic imbalance of HER2 variant in sporadic breast and ovarian cancer

Both breast and ovarian cancers are associated with HER2 receptor activation, which usually results from receptor overexpression and/or gene amplification. The HER-2 gene harbors a polymorphism at codon 655 (GTC/valine to ATC/isoleucine) in the transmembrane domain region, which has been associated with an elevated risk of breast cancer. The objective of this study was to determine whether the polymorphism is under a selection pressure during breast and ovarian carcinogenesis. The Ile/Val genotype was present in 41% (9/22) of the normal DNA of breast cancer patients. An allelic imbalance in the tumor tissue was found in three breast tumors, with overrepresentation of the Val allele. HER-2 was amplified and overexpressed in these tumors. Half of the eight ovarian tumor patients carried heterozygous Ile/Val genotypes. In contrast to breast tumors, all these ovarian cancer specimens showed the presence of the Ile allele. In our selected set of tumors, the Val allele was overrepresented in the subset of HER2-positive breast cancers and the Ile allele in serous ovarian cancer. Further analyses of tumors with known gene amplifications and overexpression may reveal novel associations between germline polymorphisms and development of sporadic tumors.