A case–control study of the HER2 Ile655Val polymorphism and risk of breast cancer in Taiwan

Human epidermal growth receptor polymorphisms (HER1-rs11543848 and HER2-rs1136201) exhibited significant association with breast cancer risk in Pashtun population of Khyber Pakhtunkhwa, Pakistan

Background and Aims

Breast cancer is the most common type of cancer in women. The genetic polymorphism in HER (HER1-rs11543848 and HER2-rs1136201) were found to be associated with breast cancer risk in different ethnicities worldwide with inconsistent results. The aim of this research study was to evaluate the association of HER1-rs11543848 and HER2-rs1136201 polymorphisms as a risk of breast cancer in Pashtun population of Khyber Pakhtunkhwa, Pakistan.

Methods

A total of 314 women including 164 breast cancer patients and 150 age and gender-matched healthy controls were enrolled from June 2021 to May 2022. All the samples were subjected to DNA extraction followed by Tetra-ARMS-PCR for genotyping and gel electrophoresis.

Results

Our results indicated that HER1-rs11543848 risk allele A (p = 0.0001) and heterozygous genotype GA (p = 0.0001) displayed highly significant association with breast cancer, while the homozygous mutant genotype AA indicated association but nonsignificant results (odds ratio [OR] = 2.637, 95% confidence interval [CI] = 1.2258-5.6756, p = 0.0833). Similarly, the HER2-rs1136201 risk allele G (p = 0.0023), the heterozygous genotype AG (p = 0.0530) and homozygous mutant genotype GG showed significant association (OR = 2.5946, 95% CI = 0.9876-6.8165, p = 0.0530) with breast cancer risk. Both the SNPs presented a higher but nonsignificant risk of breast cancer in postmenopausal women (OR = 2.242, p = 0.08 and OR = 2.009, p = 0.06). However, both the SNPs showed significant association (p < 0.005) with family history, metastasis, stage, luminal B, and TNBC.

Conclusion

In conclusion, HER1-rs11543848 and HER2-rs1136201 polymorphisms are significantly associated with the higher risk of breast cancer in Pashtun population of Khyber Pakhtunkhwa, Pakistan. These findings advocate for further exploration with larger datasets, offering promising avenues for personalized approaches in breast cancer research and potentially enhancing clinical practices for better risk assessment and targeted management strategies.

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.

Human Epidermal Growth Factor Receptor-2 gene polymorphism and breast cancer risk in women from the Northeastern region of Brazil

OBJECTIVES

In the Human Epidermal Growth Factor Receptor-2 (HER2) rs1136201 variant, the presence of the G allele may promote cellular alterations and increase breast cancer risk, in addition to enhanced cellular proliferation, tumor aggressiveness, and metastases. The aim of this study was to investigate the presence of the single-nucleotide polymorphism (SNP) variant, rs1136201, within the HER2 gene in women from the Northeastern region of Brazil and breast cancer risk.

METHODS

The study included 140 women who were divided into two groups, case (breast cancer) and control (without breast cancer), with 70 women in each group. Peripheral blood of each woman was drawn for the study of genomic Deoxyribonucleic acid (DNA) extracted from leukocytes using the genotyping technique by real-time polymerase chain reaction.

RESULTS

The GG genotype occurred in 1 woman in both groups (1.4%) (p=0.32), while the AG genotype occurred in 19 (27.2%) and 13 (18.6%) women in the case and control (p=1.00) groups, respectively. No statistically significant difference in GG and AG genotypes was observed between the case and control groups in premenopausal women (p=1.00). Furthermore, no significant difference in genotypes was observed between the groups, among postmenopausal women (p=0.14).

CONCLUSION

In this study, the HER2 rs1136201 polymorphism did not show any statistically significant association with breast cancer, both in premenopausal and postmenopausal women. Nevertheless, further studies with a larger sample size should be performed to assess the association of HER2 polymorphism with breast cancer risk in women from the Northeastern region of Brazil.

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.

Detection of HER2 Gene Polymorphism in Breast Cancer: PCR Optimization Study

Cancers are the most deadly diseases in the world and their incidences continue to increase over time. Particularly, breast cancer in females places 1^st rank among other types of cancers in term of cancer cases (23%) and death incidence (14%). Recent findings support the correlation between ^Ile655^Val SNP in the HER2 gene with breast cancer risk. Moreover, the ^Ile655^Val HER2 gene polymorphism could be a predictive factor in a neoadjuvant therapy setting. Precise detection of the ^Ile655^Val HER2 gene SNP in early breast cancer patients will be beneficial in designing the most suitable treatment and in increasing the efficacy of anticancer drugs. Here we develop a rapid and inexpensive method for ^Ile655^Val SNP detection in the HER2 gene based on allele-specific PCR technology. Two forward primers and one common reverse primer were designed to anneal specifically either on the HER2 gene fragment containing the GG genotype or to the HER2 gene fragment containing the AA genotype where one of these primers had been added with poly-GC at 5’ upstream. Moreover, to increase discrimination level, mismatch bases at the SNP site and the 3^rd base of each forward primers from 3’end were added. To test the performance of the designed primers in discriminating a polymorphism and its annealing temperature, breast cancer specimen-derived genomic DNA (with GG genotype) and pGEM_HER2/AA (with AA genotype) were used as templates in the PCR reaction. The optimal annealing temperature for SNP detection was at 51.5°C as showed by the appearance of a 150 base pair (bp) band as AA genotype (pGEM_HER2/AA template), 116bp band as GG genotype (genomic DNA template), and both types of bands as AG genotype (mix of pGEM_HER2/AA and genomic DNA template). Allelic types of breast cancer patients were also determined using this optimized method compared to sanger sequencing. The 100% accordance was shown for all types of genotypes in both methods. The allele-specific PCR in this study may have application in determining polymorphisms of the breast cancers-originated ^Ile655^Val HER2 gene.

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.

Increased risk for second primary malignancies in women with breast cancer diagnosed at young age: a population-based study in Taiwan

Studies conducted in Western countries have reported excess risks for second primary malignancies after breast cancer. However, there is little documentation of ethnic differences in these excess risks. Asian women are characterized by younger age at diagnosis of breast cancer, but very few reports are available on the incidences and risks for second primary cancers in this region. Using population-based data from the Taiwan National Cancer Registry (TNCR) for the period 1979 to 2003, we quantified standardized incidence ratios and cumulative incidence of second cancers among 53,783 women with initial diagnoses of breast cancer. Age-specific incidences showed peaks among women in their 40s, and 1,085 cases (2.02%) developed nonbreast second primary cancers. The risk for second cancers differs significantly according to age at diagnosis of breast cancer. In comparison with women diagnosed when >or=50 years (standardized incidence ratio, 0.96; 95% confidence interval; 0.89-1.04), there were significantly greater risks for bone, corpus uterine, ovarian, thyroid, esophageal, kidney and lung cancers, nonmelanoma skin cancer, and leukemia or lymphoma in women diagnosed when <50 years (standardized incidence ratio, 1.43; 95% confidence interval, 1.29-1.58). The survival probabilities differed between breast cancer patients with and without second cancers (P<0.001). After diagnosis of the second cancer, the median survival time was only 2.87 years. In conclusion, we confirmed that young age at diagnosis of breast cancer predicted a subsequently increased risk for second malignancies, and the second cancers indeed worsen survivorship in patients who survived breast cancer.