HER2 Ile655Val and PTEN IVS4 polymorphisms in patients with breast cancer

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.

Evaluation of human epidermal growth factor receptor 2 (HER2) single nucleotide polymorphisms (SNPs) in normal and breast tumor tissues and their link with breast cancer prognostic factors

Amplification of the human epidermal growth factor receptor 2 (HER2) gene is associated with worse prognosis and decreased overall survival in breast cancer patients. The HER2 gene contains several polymorphisms; two of the best-characterized HER2 polymorphisms are Ile655Val and Ala1170Pro. The aim of this study was to evaluate the association between these two HER2 polymorphisms in normal breast and breast cancer tissues and known breast cancer prognostic factors in a retrospective cohort study of 73 women with non-metastatic HER2-positive breast cancer. HER2 polymorphisms were assessed in breast cancer tissue and normal breast tissue using TaqMan assay. Ala1170Pro polymorphism in normal breast tissue was associated with age at diagnosis (p = 0.007), tumor size (p = 0.004) and lymphovascular invasion (p = 0.06). Similar significant associations in cancer tissues were observed. No association between the Ile655Val polymorphism and prognostic factors were observed. However, we found significant differences in the distribution of Ile655Val (p = 0.03) and Ala1170Pro (p = 0.01) genotypes between normal breast and breast tumor tissues. This study demonstrates that only the Ala1170Pro polymorphism is associated with prognostic factors in HER2-positive breast cancer patients. Moreover, our results suggest that both HER2 polymorphisms could play a significant role in carcinogenesis in non-metastatic HER2-positive breast cancer women.

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.

PTEN gene polymorphisms and susceptibility to oral squamous cell carcinoma in a Chinese Han population

The tumor suppressor gene phosphatase and tensin homologue (PTEN) plays a significant role in regulating cell growth, proliferation, and apoptosis. However, there are no data regarding the role of PTEN polymorphisms in the development of oral squamous cell carcinoma (OSCC). A hospital-based case-control study was conducted to investigate the potential association between PTEN polymorphisms and the risk of OSCC in a Chinese Han population. The study population comprised 201 patients with OSCC and 199 healthy controls. Seventeen single-nucleotide polymorphisms (SNPs) of PTEN were investigated and genotyped using Sequenom Mass ARRAY and iPLEX-MALDI-TOF technology. The observed genotype frequencies of these polymorphisms were in agreement with Hardy-Weinberg equilibrium in the control group (P > 0.05 for all). The heterozygous CT genotype was not associated with significantly increased risk for OSCC (OR = 0.89, 95 % CI = (0.55-1.42), P = 0.83), the TT genotype was not associated with increased risk for OSCC (OR = 1.01, 95 % CI = (0.58-1.74), P = 0.74) compared to the PTEN SNP rs1234224 homozygous CC genotype. Meanwhile, CT/TT variants were not associated with increased risk for OSCC compared with the CC genotype (OR = 0.93, 95 % CI = 0.60-1.44, P = 0.73). The T allele was not associated with significantly increased risk compared to the C allele (OR = 0.99, 95 % CI = 0.72-1.58, P = 0.69). Similar associations with the risk of OSCC were observed for the other genotypes of PTEN gene polymorphisms. There were no significant differences in the distribution of the genotype and allele frequencies of polymorphisms of the PTEN gene between the OSCC patients and controls in a Chinese Han population. Further studies are needed to clarify the specific roles of PTEN polymorphisms in the etiology of OSCC.

Association between PTEN Gene IVS4 polymorphism and risk of cancer: a meta-analysis

BACKGROUND

Phosphatase and tensin homolog (PTEN) is a well established tumor suppressor gene. Recently, increasing studies investigated the association between PTEN IVS4 polymorphism (rs3830675) and risk of various types of cancer. However, the results from the individual studies were controversial. The aim of this meta-analysis was to elucidate whether PTEN IVS4 polymorphism was associated with cancer risk.

METHODS

Databases including PubMed, Web of knowledge and Chinese National Knowledge Infrastructure (CNKI) were systematically searched to identify potentially eligible literatures. Odds ratios (OR) and their 95% confidence interval (CI) were used to assess the strength of association between PTEN IVS4 polymorphism and cancer risk.

RESULTS

A total of seven case-control studies were finally included in this meta-analysis. The pooled analysis suggested that individuals with PTEN IVS4 (-/-) genotype were significantly associated with increased risk of cancer (OR = 1.45, 95% CI = 1.19-1.76, P<0.001) and subgroup of digestive tract cancer (OR = 1.67, 95% CI = 1.28-2.18, P<0.001) compared with (+/+) genotype. The allele analysis revealed that (-) allele was significantly associated with increased risk of cancer (OR = 1.30, 95% CI = 1.12-1.50, P = 0.001) and subgroup of digestive tract cancer (OR = 1.42, 95% CI = 1.16-1.74, P = 0.001) compared with (+) allele. No significant association was observed between PTEN IVS4 (+/-) genotype and risk of cancer.

CONCLUSION

PTEN IVS4 (-/-) genotype was significantly associated with increased risk of cancer especially for digestive tract cancer compared with (+/+) genotype. The (-) allele of PTEN IVS4 (rs3830675) polymorphism was significantly associated with increased risk of cancer especially for digestive tract cancer compared with (+) allele. The recessive effect model and dominant effect model also demonstrated significant association between PTEN IVS4 (rs3830675) polymorphism and increased cancer risk especially for digestive tract cancer. Further large-scale and well-designed studies regarding different ethnicities are still required to confirm the results of our meta-analysis.

Protein tyrosine phosphatase variants in human hereditary disorders and disease susceptibilities

Reversible tyrosine phosphorylation of proteins is a key regulatory mechanism to steer normal development and physiological functioning of multicellular organisms. Phosphotyrosine dephosphorylation is exerted by members of the super-family of protein tyrosine phosphatase (PTP) enzymes and many play such essential roles that a wide variety of hereditary disorders and disease susceptibilities in man are caused by PTP alleles. More than two decades of PTP research has resulted in a collection of PTP genetic variants with corresponding consequences at the molecular, cellular and physiological level. Here we present a comprehensive overview of these PTP gene variants that have been linked to disease states in man. Although the findings have direct bearing for disease diagnostics and for research on disease etiology, more work is necessary to translate this into therapies that alleviate the burden of these hereditary disorders and disease susceptibilities in man.