HER2 polymorphism and breast cancer risk in Portugal

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.

Frequency of I655V SNP of HER-2/neu in colorectal cancer: a study from India

The present study was conducted to determine the prognostic significance of I655V SNP (rs1136201) is a genetic one in HER-2 oncoprotein in cases of colorectal cancer (CRC). We conducted a case-control study analysing 83 subjects (naïve primary CRC cases) who underwent CRC biopsy/colectomy and included 57 healthy control subjects. Analysis of HER-2 polymorphism was done by PCR-RFLP technique. The mean age was found to be 55.9 years; median age was 56 years and mode age was 54 years with a range of 43 (30-73). Males constitute 63 (75.9%) and females constitute 20 (24.1%) of patient population. According to gradewise distribution, 12 (14.45%) patients were of Grade I, 53 (63.85%) of Grade II, and 18 (21.68%) were of Grade III. We found out that out of 83 patients, 52 (62.65%) were of homozygous wild type (A/A; Ile/Ile); 27 (32.53%) were of heterozygous type (A/G; Ile/Val) and 4 (4.81%) were of homozygous mutant type (G/G; Val/Val). Allelic frequency of Ile (A) was found out to be 0.79 and that of Val (G) is 0.21 and were not significantly different from the healthy control population. Fischer's exact p value obtained was 0.86.

Genomic alterations associated with HER2+ breast cancer risk and clinical outcome in response to trastuzumab

Human epidermal growth factor receptor 2 positive (HER2+) breast cancer (BC) is an aggressive BC subtype characterized by HER2 overexpression/amplification. Genomic alterations of HER2 and others have been reported to be associated with, HER2 overexpression and prediction of trastuzumab-response. Here, we aimed at identifying germline and somatic alterations associated with HER2+ BC and evaluating their association with clinical outcome in response to trastuzumab therapy given to HER2+ BC patients. Global Sequencing Array (GSA) and polymerase chain reaction-restriction length polymorphism (PCR-RFLP) techniques were used to determine alterations in HER2 and other HER2-interacting as well as signaling-related genes in HER2+ BC. In addition, 20 formalin fixed paraffin-embedded tissue samples were also evaluated by GSA for identifying significant variations associated with HER + BC as well as response to trastuzumab therapy. A germline variant in HER2 (I655V) was found to be significantly associated with the risk of the disease (p < 0.01). A nonsense mutation in PTPN11 (K99X), a pathogenic CCND1 splice site variant (P241P), a hotspot missense mutation in PIK3CA (E542K) and a hotspot missense mutation in TP53 (R249S); were observed in 25%, 75%, 30% and 40% of the HER2+ BC tissue samples, respectively. Mutant CCND1 (P241P) and PIK3CA (E542K) were found to be significantly associated with reduced disease-free survival (DFS) in patients treated with trastuzumab (p: 0.018 and 0.005, respectively). These results indicate that HER2, PTPN11, CCND1 and PIK3CA genes are important biomarkers in HER2+ BC. Moreover, the patients harboring mutant CCND1 and PIK3CA exhibit a poorer clinical outcome as compared to those carrying wild-type CCND1 and PIK3CA.

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.

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.

No association of hypoxia inducible factor-1α gene polymorphisms with breast cancer in North-West Indians

BACKGROUND

Hypoxia inducible factor-1 alpha (HIF-1α) is the key regulator of cellular responses to hypoxia and plays a central role in tumour growth. Presence of Single nucleotide polymorphisms (SNPs) in the critical regulatory domains of HIF-1α may result in the overexpression of the protein and subsequent changes in the expression of the downstream target genes. The aim of study was to investigate the association of three SNPs (g.C111A, g.C1772T and g.G1790A) of HIF-1α with the risk of breast cancer in North Indian sporadic breast cancer patients.

MATERIALS AND METHODS

A total of 400 subjects, including 200 healthy controls and 200 patients with breast cancer were recruited in this study. Genotypes were determined using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.

RESULTS

The CC and CA genotype frequency of HIF-1α g.C111A polymorphism was 100 vs 99% and 0 vs 1% in breast cancer patients and healthy controls respectively. The frequencies of CC, CT and TT genotype of g.C1772T polymorphism were 76 vs 74.5%, 19 vs 21% and 5 vs 4.5% in breast cancer patients and control individuals respectively. There was no significant difference in genotype and allele frequencies of HIF-1α g.C1772T polymorphism between cases and control individuals (p>0.05). For g.G1790A genotypes, all patients and controls had only GG genotype.

CONCLUSIONS

The three HIF-1α polymorphisms (g.C111A, g.C1772T and g.G1790A) are not associated with breast cancer risk in North-West Indian patients.

TP53 polymorphisms in sporadic North Indian breast cancer patients

BACKGROUND

The purpose of this study was to evaluate the potential association of five (p.P47S, p.R72P, PIN3 Ins16bp, p.R213R and r.13494g>a) polymorphisms of TP53 with the risk of developing breast cancer in North Indian Punjabi population.

METHODS

We screened DNA samples of 200 sporadic breast cancer patients (197 females and 3 males) and 200 unrelated healthy, gender and age matched individuals for the polymorphisms.

RESULTS

For the p.P47S polymorphism, we observed the PP genotype in 99.5% of the patients and PS genotype in only 1 patient. All the controls had the wild type PP genotype. The frequency of RR, RP and PP genotype of p.R72P was 23.5% vs 33.5%, 51.5% vs 45.5% and 25% vs 21% in patients and controls respectively. Heterozygous (RP) genotype was increased in breast cancer patients as compared to controls (51.5 vs 45.5%) and showed 1.61 fold significantly increased risk for breast cancer (OR=1.61, 95% CI, 1.01-2.58, p=0.04). In breast cancer patients the frequencies of A1A1, A1A2 and A2A2 genotypes of PIN3 Ins16bp polymorphism were 67%, 26% and 7% respectively whereas in controls the genotype frequencies were 68.5%, 27.5% and 4% respectively, with no significant difference. For p.R213R (c.639A>G), all individuals had homozygous wild type genotype. The frequencies of GG, GA and AA genotypes of TP53 r.13494g>a polymorphism were 62 vs 67.5%, 33 vs 28% and 5 vs 4.5% in patients and controls respectively, again without significant difference. We observed that RP- A1A1 genotype combination of p.R72P and PIN3 Ins16bp and RP-GG combination of p.R72P and r.13494g>a polymorphism showed significant risk of breast cancer (OR=1.65, 95%CI: 0.98-2.78, p=0.05; OR=1.72, 95%CI: 1.01-2.92, p=0.04).

CONCLUSION

The results of present study indicated that among the five TP53 polymorphisms investigated, the p.R72P polymorphism, and the RP-A1A1 and RP-GG genotype combination contribute to breast cancer susceptibility in North Indians.

Genetic polymorphisms and cervical cancer development: ATM G5557A and p53bp1 C1236G

Persistent infections by high-risk types of human papillomavirus (HPV) have been established as the etiological agent of cervical cancer. The integration of the HPV genome into the host genome is a crucial step in cervical carcinogenesis, although, correct activation of DNA damage repair pathways will avoid the development of cancer. Recent data indicate that several polymorphisms of key regulators from the DNA damage repair pathway (i.e. 53BP1 and ATM) are associated with cancer development susceptibility. We have developed a hospital-based retrospective study considering 429 cervical specimens from women with different cervical lesions including invasive carcinoma. This study aimed to evaluate the role of the ATM D1853N (5557G>A) and 53bp1 D353E (1236C>G) polymorphisms in the development of cervical cancer, using TaqMan SNP Genotyping Assays. Statistical analysis revealed that ATM 5557GG homozygous individuals (OR=1.94; p=0.044) are at increased risk of developing LSIL, while for the 53BP1 1236C>G polymorphism no association was found. Nevertheless, we observed a tendency for an increased risk of LSIL in 53BP1 1236C allele carriers (OR=1.63; p=0.069). Logistic regression adjusted for age revealed no significant differences from the non-adjusted analysis. This is the first study to evaluate the role of ATM G5557A and P53BP1 C1236G polymorphisms in cervical cancer susceptibility. This study reveals a possible trend of both polymorphisms for a genetic susceptibility pattern of cervical cancer development. Hence, our results may be of interest for future understanding of the progression of cervical cancer.

Implications of single nucleotide polymorphisms in CD44 exon 2 for risk of breast cancer

CD44 is a cell-surface glycoprotein involved in many cellular functions including lymphocyte activation, recirculation and homing, hematopoiesis and tumor metastasis, suggesting that CD44 may play an important role in breast cancer development. In this study, we examined whether CD44 exon 2 polymorphisms are associated with increased susceptibility to breast cancer. Direct nucleotide sequencing analysis showed that multiple single nucleotide polymorphisms were present in the CD44 exon 2 coding region in female patients with breast cancer. There was no significant difference in the frequency of any one single nucleotide polymorphism in the CD44 exon 2 coding region between patients with breast cancer and normal donors. However, CD44 polymorphisms in the CD44 exon 2 coding region were identified in approximately 40% of patients with breast cancer, which was significantly higher than in normal donors (odds ratio, 9.34; 95% confidence interval = 2.58-33.82; P < 0.0001). The Wilcoxon-Mann-Whitney test analysis showed that the patients with the CD44 polymorphisms in CD44 exon 2 coding sequence had breast cancer at earlier ages, 49 ± 3 versus 62 ± 2 years (P < 0.0005), and larger tumor burdens (4.9 ± 1.22 vs. 1.6 ± 0.15 mm, P < 0.01) at the time of diagnosis. Interestingly, African-American female patients having the CD44 polymorphisms in CD44 exon 2 coding sequence were diagnosed with breast cancer at very young age (41 ± 2 years). Our results show that CD44 exon 2 polymorphisms are associated with breast cancer development, and such analysis may be effectively used in the evaluation of risk, prediction of cancer, prevention, diagnosis, and epidemiological studies of breast cancer.

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.

Study on the association of COX-2 genetic polymorphisms with risk of gastric cancer in high incidence Hexi area of Gansu province in China

To investigate the possible association of polymorphisms, cyclooxygenase-2 (COX-2) promoter region -899G>C, COX-2 codon 587G>A, with risk of gastric cancer in the high incidence Hexi area of Gansu province in China. Blood samples from 140 patients with gastric carcinoma and 125 normal persons were collected in Hexi area of Gansu province in China. Polymorphisms of COX-2 -899G>A and COX-2 587G>A were genotyped by PCR-TaqMan. For detection Helicobacter pylori infection, Warhin-Starry staining was used. Three kinds of polymorphisms of COX-2 -899G>C were GG, GC and CC. The frequencies in gastric cancer patients were 72.9, 21.4 and 5.7%, and the frequencies in controls were 84.0, 12.8 and 3.2%, respectively. COX-2 -899C carrier (GC + CC) increased risk of gastric carcinoma with an odds ratio 1.950 (95% CI: 1.067-3.586, P=0.029). The genotype of COX-2 587G>A polymorphism were GG, GA and AA. The frequencies in patients group were 86.4, 11.4 and 2.2%, and the frequencies in controls were 89.6, 9.6 and 0.8%, respectively. There was no significant difference between cases and controls in each genotype. Helicobacter pylori infection rate was 68.6% in patients group and 50.4% in healthy controls. Helicobacter pylori infection rate in gastric cancer patients was remarkably higher than that in normal people (OR: 2.147, 95% CI: 1.302-3.541, P=0.003). Stratification analysis was showed that COX-2 -899C carrier genotype with Helicobacter pylori infection was significantly higher in cases than that in healthy controls (OR: 4.000, 95% CI: 1.638-9.770). The polymorphism of COX-2 -899G>C could be a risk factor for gastric cancer in high incidence Hexi area of Gansu Province in China. COX-2 -899C carrier genotype and Helicobacter pylori positive infection may have a synergistic effect on gastric cancer in high incidence Hexi area of Gansu Province in China. However, the polymorphisms of COX-2 587G>A is no association with gastric cancer in the high incidence Hexi area of Gansu Province in China.

Overall survival in women with breast cancer: the influence of pepsinogen C gene polymorphism

We aimed to study the role of an insertion/deletion polymorphism in the Pepsinogen C (PGC) gene in the clinical outcome of 172 breast cancer patients. The six polymorphic alleles were amplified using PCR. Our results indicate that patients carrying the allele 6 present a higher 5-year survival mean (83.4% of 6 allele carriers were alive at 5 years vs. only 68.6% of noncarriers, p=0.001), suggesting a role for this polymorphism in the outcome of breast cancer patients. We hypothesize that PGC polymorphism can be a predictive biomarker in breast cancer, contributing to an individual profile of great interest in clinical oncology.

Estrogens metabolism associated with polymorphisms: influence of COMT G482a genotype on age at onset of canine mammary tumors

Catechol-O-methyltransferase (COMT) is an important enzyme participating in inactivation of carcinogenic oestrogen metabolites. In humans there is a single nucleotide polymorphism in COMT gene (COMT val158met) that has been associated with an increased risk for developing breast cancer. In dogs, there is a single nucleotide polymorphism in COMT gene (G482A), but its relation with mammary carcinogenesis has never been investigated. The aim of this study was to focus on the evaluation of such polymorphism as a risk factor for the development of mammary tumors in bitches and on the analysis of its relationship with some clinicopathologic features (dog's age and weight, number and histologic type of the lesions, lymph node metastasis) of canine mammary neoplasms. A case-control study was conducted analyzing 90 bitches with mammary tumors and 84 bitches without evidence of neoplastic disease. The COMT G482A polymorphism was analyzed by PCR-RFLP. We found a protective effect of the polymorphism in age of onset of mammary tumors, although we could not establish a significant association between COMT genotype and other clinicopathologic parameters nor with mammary tumor risk overall. Animals carrying the variant allele have a threefold likelihood of developing mammary tumors after 9 years of age in comparison with noncarriers. The Kaplan-Meier method revealed significant differences in the waiting time for onset of malignant disease for A allele carrier (12.46 years) and noncarrier (11.13 years) animals. This investigation constitutes the first case-control study designed to assess the relationship between polymorphic genes and mammary tumor risk in dogs. Our results point to the combined effect of COMT genotype with other genetic and/or environmental risk factors as important key factors for mammary tumor etiopathogenesis.

Importance of TP53 codon 72 and intron 3 duplication 16bp polymorphisms in prediction of susceptibility on breast cancer

Background

TP53 is one of major tumour suppressor genes being essential in preservation of genome integrity. Two very common polymorphisms have been demonstrated to contribute to cancer susceptibility and tumour behaviour. The purpose of this study was to evaluate the role of Arg72Pro and PIN3 Ins16bp polymorphisms in TP53 gene as genetic susceptibility and predictive markers to breast cancer.

Methods

We analysed DNA samples from 264 breast cancer patients and 440 controls, for TP53 Arg72Pro and PIN3 Ins16bp polymorphisms using PCR-RFLP.

Results

We observed that women with A2A2 genotype have increased risk for developing breast cancer, either in women with or without familial history (FH) of the disease (OR = 4.40, 95% CI 1.60–12.0; p = 0.004; OR = 3.88, 95% CI 1.18–12.8; p = 0.026, respectively). In haplotype analysis, statistically significant differences were found between TP53 Arg-A2 haplotype frequencies and familial breast cancer cases and the respective control group (OR = 2.10, 95% CI 1.08–4.06; p = 0.028). Furthermore, both TP53 polymorphisms are associated with higher incidence of lymph node metastases.

Conclusion

Our findings suggest TP53 PIN3 Ins16bp polymorphism as a real risk modifier in breast cancer disease, either in sporadic and familial breast cancer. Furthermore, both TP53 polymorphisms are associated with higher incidence of lymph node metastases.

DNA repair polymorphisms might contribute differentially on familial and sporadic breast cancer susceptibility: a study on a Portuguese population

The purpose of this study was to evaluate the role of polymorphisms in DNA repair genes as genetic indicators of susceptibility to familial and sporadic breast cancer. We analysed DNA samples from 285 breast cancer patients and 442 control subjects, for XRCC1 Arg399Gln, XPD Lys751Gln, RAD51 G135C and XRCC3 Thr241Met polymorphisms using PCR-RFLP. We observed that women carriers of XRCC1 399Gln genotypes and without family history of breast cancer have a protective effect concerning this disease (OR = 0.54 95% CI 0.35-0.84; p = 0.006). Furthermore, we found that carriers of XRCC3 241Met genotypes without FH have an increased susceptibility of breast cancer (OR = 2.21 95% CI 1.42-3.44; p < 0.001). Additionally, we verified an increased risk of breast cancer in women with FH and carrying RAD51 135C genotypes (OR = 2.17 95% CI 1.19-3.98; p = 0.012). Our results suggest XRCC1 Arg399Gln and XRCC3 Thr241Met DNA repair polymorphisms as important biomarkers to sporadic breast cancer susceptibility, as well as, RAD51 G135C polymorphism as a real risk modifier in familial breast cancer cases.

-765G > C COX-2 polymorphism may be a susceptibility marker for gastric adenocarcinoma in patients with atrophy or intestinal metaplasia

AIM: To investigate the relationship between the -765G > C COX-2 polymorphism and the development of different gastric lesions: atrophy or intestinal metaplasia and gastric adenocarcinoma.

METHODS: A cross-sectional study was performed involving 320 Portuguese individuals (210 without evidence of neoplastic disease, 73 patients with gastric adenocarcinomas and 37 with atrophy or intestinal metaplasia) using a PCR-RFLP method.

RESULTS: -765C allele was overrepresented in the patients with gastric adenocarcinoma (51%) when compared either with the control group (38%) or patients with atrophy or intestinal metaplasia (27%). Callele was found to be very common in our population (0.22), and a multivariate logistic regression analysis revealed nearly 3-fold increased risk for the progression to gastric adenocarcinoma in patients with atrophy or intestinal metaplasia carrying the -765C allele (OR = 2.67, 95% CI = 1.03-6.93; P = 0.04).

CONCLUSION: -765C carrier status should be considered as another susceptibility marker for gastric adenocarcinoma development in patients with atrophy or intestinal metaplasia.

Gastric cancer in a Caucasian population: Role of pepsinogen C genetic variants

AIM: To study the role of an insertion/deletion polymorphism in the pepsinogen C (PGC) gene, an effective marker for terminal differentiation of the stomach mucosa, in the susceptibility to the development of gastric lesions.

METHODS: The study was performed with 99 samples of known gastric lesions and 127 samples without evidence of neoplastic disease. PCR was employed and the 6 polymorphic alleles were amplified: Allele 1 (510 bp), Allele 2 (480 bp), Allele 3/4 (450/460 bp), Allele 5 (400 bp) and Allele 6 (310 bp).

RESULTS: Our results revealed that Allele 6 carriers seemed to have protection against the development of any gastric lesion (OR = 0.34; P < 0.001), non-dysplastic lesions associated with gastric adenocarcinoma such as atrophy or intestinal metaplasia (OR = 0.28; P < 0.001) or invasive GC (OR = 0.39; P = 0.004).

CONCLUSION: Our study reveals that the Allele 6 carrier status has a protective role in the development of gastric lesions, probably due to its association with higher expression of PGC. Moreover, the frequency of Allele 6 carriers in the control group is far higher than that obtained in Asian populations, which might represent a genetic gap between Caucasian and Asian populations.

The influence of HER2 genotypes as molecular markers in ovarian cancer outcome

A relevant clinical problem in the treatment of ovarian cancer (OC) is the development of resistance to chemotherapy, frequently due to genetic variations in enzymes and receptors. Changes in the HER2 receptor have been associated with breast and ovarian cancers. The role of a polymorphism in the HER2 gene in the clinical outcome of OC patients was investigated in this study. We characterized DNA samples from 111 patients with OC treated with cisplatin and paclitaxel, using PCR-RFLP. Our results indicate that patients carrying the valine homozygotic genotype present a lower overall survival mean, suggesting a role for this polymorphism in the outcome of ovarian cancer patients. The G allele has been implicated in the formation of active HER2 receptors, with a more aggressive phenotype. We hypothesize that HER2 genotypes can be predictive biomarkers in ovarian cancer, contributing to a genetic individual profile of great interest in clinical oncology.

TP53 codon 72 polymorphism and risk for cervical cancer in Portugal

High-risk human papillomavirus are essential for the development of cervical cancer; however, TP53 is the most frequently altered tumor suppressor gene among tumors and is described as a cofactor for cervical carcinogenesis. TP53 has two common polymorphic forms encoding either proline or arginine, at position 72, and the presence of homozygous arginine has been reported as a risk factor for cervical cancer in many populations. We evaluated the effect of this TP53 polymorphism in a northern Portuguese population. We analyzed blood samples of 385 women; 20 with low-grade squamous intraepithelial lesion (SIL), 56 with high-grade SIL, 164 with invasive cervical cancer, and 145 healthy controls, using allele specific-polymerase chain reaction methodology. We observed an increased frequency of the Arg/Arg genotype in the cancer group, but no statistical significance was found between cases and controls (P>0.05). Our results indicate that there is no association between the presence of the Arg allele in codon 72 of TP53 polymorphism and risk of cervical cancer in our population.