Prevalence of tobacco use among cancer patients in Iran: a systematic review and meta-analysis.

BACKGROUND: The prevalence of tobacco use among various cancer types in Iran remains a significant concern, necessitating a comprehensive analysis to understand the extent and patterns of consumption. This study aimed to systematically review and analyze existing literature to delineate the prevalence of tobacco use across different cancer types in Iran, thereby providing a robust basis for future interventions and policy formulations. METHODS: Adhering to the PRISMA guidelines, we conducted a systematic review and meta-analysis of literature available in PubMed and Scopus databases. The initial search identified 351 records, out of which 44 studies were selected based on their relevance and design. These studies spanned various time frames, starting from the 2001s up until 2022, and encompassed diverse geographical locations and cancer types in Iran. To avoid bias and potential data overlap, we opted to incorporate a single comprehensive study from the Golestan Cohort, encompassing all data, while excluding 10 other studies. Our final analysis incorporated data from 34 studies, which accounted for 15,425 patients and 5,890 reported smokers. Statistical analyses were performed to calculate the overall proportion of tobacco consumption and to conduct subgroup analyses based on different variables such as cancer types, gender, geographical locations, and types of tobacco used. RESULTS: The analysis revealed a substantial prevalence of tobacco use among cancer patients in Iran, with an overall consumption rate of 43%. This rate varied significantly, ranging from 10 to 88% across individual studies. Subgroup analyses further highlighted disparities in tobacco consumption rates across different demographics, geographic areas, and cancer types. Notably, the 'ever' smokers category exhibited the highest prevalence of tobacco use. The study also identified a worrying trend of high cigarette smoking rates, along with variable consumption patterns of other forms of tobacco, including waterpipe, 'Naas', and 'Pipe'. CONCLUSIONS: This systematic review and meta-analysis underscores a significant association between tobacco consumption and various cancer types in Iran, with a prevalence rate among cancer patients being three times higher than the average Iranian population. The findings indicate substantial heterogeneity in tobacco use patterns, emphasizing the need for targeted interventions to address this pressing health issue. The study serves as a critical resource for shaping future policies and strategies aimed at curbing tobacco use and mitigating its adverse effects on cancer prevalence in Iran.

Opium use and risk of lung cancer: A multicenter case-control study in Iran.

Opium use was recently classified as a human carcinogen for lung cancer by the International Agency for Research on Cancer. We conducted a large, multicenter case-control study evaluating the association between opium use and the risk of lung cancer. We recruited 627 cases and 3477 controls from May 2017 to July 2020. We used unconditional logistic regression analyses to estimate the odds ratios (OR) and 95% confidence intervals (CI) and measured the association between opium use and the risk of lung cancer. The ORs were adjusted for the residential place, age, gender, socioeconomic status, cigarettes, and water pipe smoking. We found a 3.6-fold risk of lung cancer for regular opium users compared to never users (95% CI: 2.9, 4.6). There was a strong dose-response association between a cumulative count of opium use and lung cancer risk. The OR for regular opium use was higher for small cell carcinoma than in other histology (8.3, 95% CI: 4.8, 14.4). The OR of developing lung cancer among opium users was higher in females (7.4, 95% CI: 3.8, 14.5) than in males (3.3, 95% CI: 2.6, 4.2). The OR for users of both opium and tobacco was 13.4 (95% CI: 10.2, 17.7) compared to nonusers of anything. The risk of developing lung cancer is higher in regular opium users, and these results strengthen the conclusions on the carcinogenicity of opium. The association is stronger for small cell carcinoma cases than in other histology.

Plasma microRNA-195, -34c, and - 1246 as novel biomarkers for the diagnosis of trastuzumab-resistant HER2-positive breast cancer patients.

Recently, miRNAs have been regarded as potential candidates for mediating therapeutic functions by targeting genes related to drug response. In this study, we suggested that plasma miRNAs may be correlated with response to trastuzumab in HER2-positive breast cancer patients. To determine whether miR-195, miR-23b-3p, miR-1246, and miR-34c-3p are involved in trastuzumab resistance, we screened their expressions in the BT-474 cell line, which was followed by plasma analysis from 20 trastuzumab-resistant HER2-positive breast cancer patients and 20 nonresistance subjects. Then, TargetScan, Pictar, and miRDB were applied to find the possible targets of the selected miRNAs. In addition, the expression status of admitted targets was evaluated. Our results showed that in resistant BT-474 cells, miR-1246, and miR-23b-3p were significantly upregulated, and miR-195-5p and miR-34c-3p were downregulated. In plasma analysis, we found miR-195-5p, miR-34c-3p, and miR-1246 meaningfully diminished in the resistant group, while the expression of miR-23b-3p was not statistically different. The expression levels of confirmed targets by qRT-PCR showed that the expression of RAF1, AKT3, c-MET, CCND1, PHLPP2, MYB, MAP2K1, and PTEN was significantly upregulated, while the expression of CCNG2 was significantly downregulated. The networks of miRNAs with their confirmed targets improved comprehension of miRNA-mediated therapeutic responses to trastuzumab and might be proposed for more characterization of miRNA functions. Moreover, these data indicated that miR-195-5p, miR-34c-3p, and miR-1246 could be possible biomarkers for prognosis and early detection of the trastuzumab-resistant group from the sensitive group of HER2-positive breast cancer patients.

Opium use and risk of colorectal cancer: a multi-center case-referent study in Iran.

BACKGROUND: Opium use has been associated with an increased risk of cancers of the lung, oesophagus, and pancreas, and it was recently classified by the International Agency for Cancer Research as carcinogenic to humans. It is not clear whether opium also increases the risk of colorectal cancer (CRC). The aim of our study was to assess the association between various metrics of opium use and the risk of CRC. METHODS: This case-referent study from seven provinces in Iran comprised 848 CRC cases and 3215 referents. Data on opium use (duration, amount, frequency) and potential confounders were collected by trained interviewers. Multivariable unconditional logistic regression models were used to measure odds ratios (OR) adjusted for age, gender, province, marital status, family history of CRC-linked cancers, consumption of red meat, fruits and vegetables, body shape, occupational physical activity, and socioeconomic status. RESULTS: Regular opium consumption was not associated with the risk of CRC (OR 0.9, 95% confidence interval, CI: 0.7, 1.2) compared to subjects who never used opium. However, frequent opium use more than twice a day was associated with an increased risk of CRC compared to non-users of opium (OR: 2.0, 95% CI: 1.1, 3.8; p for quadratic trend 0.008). CONCLUSION: There seems to be no overall association between opium use and CRC, but the risk of CRC might be increased among persons who use opium many times a day.

Opium use and the risk of head and neck squamous cell carcinoma.

Scant evidence exists to support the association of opium use with head and neck cancer, limited to the larynx and oral cavity. In a multicenter case-control study-Iran Opium and Cancer study, we recruited 633 cases of head and neck squamous cell carcinoma (HNSCC) (254 lip and oral cavity, 54 pharynx, 327 larynx and 28 other subsites within the head and neck) and 3065 frequency-matched controls from April 2016 to April 2019. Odds ratios (ORs) for opium use and 95% confidence intervals (95% CIs) were obtained using mixed-effects logistic regression because of heterogeneity among centers. The adjusted OR (95% CI) for regular opium use was 3.76 (2.96-4.79) for all HNSCC combined. Strong dose-response effects were observed by frequency or amount of use, and duration of use. Regular opium uses significantly increased the risk of HNSCC of the pharynx, larynx and other subsites within the head and neck with OR (95% CI) of 2.90 (1.40-6.02), 6.55 (4.69-9.13) and 5.95 (2.41-14.71), respectively. The observed associations were significant even among never tobacco smokers (including cigarette and water-pipe smoking). Moreover, by the multiplicative interaction scale, the effect of opium use could be varied by cigarette smoking on HNSCC, 8.16 (6.20-10.74). For the first time, the current study showed opium users have an increased risk of several anatomic subsites of HNSCC.

Role of regulatory miRNAs of the PI3K/AKT/mTOR signaling in the pathogenesis of hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the common malignant human tumors with high morbidity worldwide. Aberrant activation of the oncogenic phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) signaling is related to clinicopathological features of HCC. Emerging data revealed that microRNAs (miRNAs) have prominent implications for regulating cellular proliferation, differentiation, apoptosis, and metabolism through targeting the PI3K/AKT/mTOR signaling axis. The recognition of the crucial role of miRNAs in hepatocarcinogenesis represents a promising area to identify novel anticancer therapeutics for HCC. The present study summarizes the major findings about the regulatory role of miRNAs in the PI3K/AKT/mTOR pathway in the pathogenesis of HCC.

Association of cyclin-dependent kinase inhibitor 2A/B with increased risk of developing breast cancer.

There is a growing body of data reporting the association of genetic alterations in chromosome 9P21 with the risk of developing cancer. In the current study, we studied the association of a genetic variant in CDKN2A/B, rs1333049, with the risk of developing breast cancer. A total of 339 participants with and without breast cancer entered to the study. Genotyping was done by the TaqMan real-time polymerase chain reaction (RT-PCR) method and gene expression analysis was ran by RT-PCR. Our data showed that the minor allele homozygote in the total population was 10%, whereas for heterozygote was 38%. The dominant genetic model demonstrated that individuals with breast cancer had advanced TNM classification. Moreover, the logistic regression revealed that individuals who had CC/CG genotypes might have an enhanced risk of developing breast cancer when compared to the holders of GG genotype (e.g., OR = 2.8; 95% CI,1.4-5.4; p = .001), after regulated for confounders; age and body mass index. Furthermore, our analysis showed that the CDKN2A/B gene was downregulated in patients (p < .001). We showed a meaningful relationship of CDKN2A/B with the risk of breast cancer, cancer, showing the importance of studies in great sample size and several centers for studying the value of the marker as a risk classification in the management of patients with breast cancer.

The association between genetic variants in the genes for cytochrome P450 B1 and ATP-binding cassette transporter genes and breast cancer risk.

Breast cancer is among the most common malignancies in women. Recent studies have shown that polymorphisms in genes involved in the metabolism and transport of anticancer drugs are associated with outcomes of several malignancies, e.g., breast cancer. In this study we evaluate whether CYP1B1/rs1056836 and ABCB1/rs2032582 gene variants are associated with breast cancer. Eighty eight cases and 200 controls, were genotyped for polymorphisms of the CYP1B1 and ABCB1 genes using Taqman®-based methods. Logistic regression was also used to test the associations between breast cancer risk and the various genotypes involved. The GG genotype of rs2032582 locus had a frequency of 43.5% with 0.38 MAF; while the GT and TT genotypes in the control group were 40% and 16.5%, respectively. The GG, GT and TT genotype frequencies in the patients with breast cancer were 45.5%, 12.5% and 26.1%, respectively. An association was observed between the TT genotype of ABCB1/rs2032582 locus and a larger breast cancer tumor size (P < 0.05). However, neither the relationship between the CYP1B1 polymorphism and breast cancer type nor the risk of breast cancer were statistically significant. Our data suggest a potential association of the ABCB1 genetic variant with breast cancer tumor size, however further investigation in a larger population is necessary to show its value as a risk stratification biomarker.

Epidemiology of lung cancer in northeast of Iran: A 25-year study of 939 patients.

Background: Lung cancer (LC) is a global public health priority. In this study, the epidemiology and current trends of primary LCs were investigated in northeast of Iran. Methods: Demographic and pathologic records of primary LCs during 1985-2012 in Mashhad (capital of northeast of Iran) were reviewed. Data were obtained from archives of the largest referral oncologic hospital and the only private outpatient radiation-oncologic clinic in the region. To investigate trends, study duration was classified into 3 periods: 1985-1995, 1995-2005, and 2005-2012. Patients were placed in one of these 3 groups, based on the date of their pathologic diagnosis. Data were analyzed by SPSS 16 software. T test, chi-squared, and ANOVA tests were used for data analysis, and statistical significant level was set at < 0.05. Results: Among 939 cases with pathologic diagnosis of primary LC, male-to-female ratio was 2.36. Mean±SD age at diagnosis was 61.47±12.01 years in males and 58.45±12.75 in females (p=0.001). Squamous cell carcinoma (SCC) was the most frequent pathologic subtype. Mean age at diagnosis and rate of smokers were unchanged during the study (p= 0.978 and 0.153, respectively). Relative frequency of leading pathologic subtypes changed in 3 intervals (p<0.001): it was increasing in adenocarcinoma and large cell carcinoma and decreasing in SCC and small cell lung cancer (SCLC). There were statistically significant differences in the mean age at diagnosis (p<0.001), rate of smokers (p<0.001), and male-to-female ratio (p=0.011) between leading pathologic subtypes. Conclusion: Similar to universal picture, rate of adenocarcinoma in northeast of Iran was rising during recent decades, especially among younger patients, women, and nonsmokers. These trends are indicative of changes in exposures and smoking habits and reveal the need for regional studies in these contexts.

A genetic variant in CDKN2A/2B locus was associated with poor prognosis in patients with esophageal squamous cell carcinoma.

Esophageal squamous cell carcinoma (ESCC) is among the leading causes of cancer related death. Despite of extensive efforts in identifying valid cancer prognostic biomarkers, only a very small number of markers have been identified. Several genetic variants in the 9p21 region have been identified that are associated with the risk of multiple cancers. Here, we explored the association of two genetic variants in the 9p21 region, CDKN2A/B, rs10811661, and rs1333049 for the first time in 273 subjects with, or without ESCC. We observed that the patients with ESCC had a higher frequency of a TT genotype for rs10811661 than individuals in the control group, and this polymorphism was also associated with tumor size. Moreover, a CC genotype for the rs1333049 polymorphism was associated with a reduced overall survival (OS) of patients with ESCC. In particular, patients with a CC (rs1333049) genotype had a significantly shorter OS (CC genotype: 34.5 ± 8.9 months vs. CG+GG: 47.7 ± 5.9 months; p value = 0.03). We have also shown the association of a novel genetic variant in CDKN2B gene with clinical outcome of patients with ESCC. Further investigations are warranted in a larger population to explore the value of emerging markers as a risk stratification marker in ESCC.

Targeted therapies in pancreatic cancer: Promises and failures.

Pancreatic ductal adenocarcinoma (PDAC) is an incidence rate nearly equal to its mortality rate. The poor prognosis of the disease can be explained by the absence of effective biomarkers for screening and early detection, together with the aggressive behavior and resistance to the currently available chemotherapy. The therapeutic failure can also be attributed to the inter-/intratumor genetic heterogeneity and the abundance of tumor stroma that occupies the majority of the tumor mass. Gemcitabine is used in the treatment of PDAC; however, the response rate is less than 12%. A recent phase III trial revealed that the combination of oxaliplatin, irinotecan, fluorouracil, and leucovorin could be an option for the treatment of metastatic PDAC patients with good performance status, although these approaches can result in high toxicity level. Further investigations are required to develop innovative anticancer agents that either improve gemcitabine activity, within novel combinatorial approaches or acts with a better efficacy than gemcitabine. The aim of the current review is to give an overview of preclinical and clinical studies targeting key dysregulated signaling pathways in PDAC.

Current status and future prospects of transforming growth factor-ß as a potential prognostic and therapeutic target in the treatment of breast cancer.

The transforming growth factor-ß (TGF-ß) signaling pathway is one of the important pathways involved in the cancer cell proliferation, invasion, migration, angiogenesis, apoptosis, as well as in metastasis by agitation or invasion of metastasis-related factors, including matrix metalloproteinase (MMP), epithelial-to-mesenchymal transition (EMT), tumor microenvironment (TME), cancer stem cells (CSCs), and cell adhesion molecules (CAMs). These data suggest its potential value as a therapeutic object in the treatment of malignancies including breast cancer. Several pharmacological approaches have been established to suppress TGF-ß pathway; such as vaccines, small molecular inhibitors, antisense oligonucleotides, and monoclonal antibodies. Some of these are now approved by the US Food and Drug Administration for targeting the TGF-ß signaling pathway. This study attempts to summarize the current data about the functions of TGF-ß in cancer cells, and their probable application in the cancer therapy with a specific emphasis on recent preclinical and clinical research in the treatment of breast cancer and its prognostic value.

Therapeutic potential of targeting the Wnt/ß-catenin pathway in the treatment of pancreatic cancer.

The Wnt/ß-catenin pathway is an important, dysregulated pathway in several tumor types, including pancreatic ductal adenocarcinoma. Although the activation of this pathway is an important component of normal development, its aberrant activation resulting from activating or inactivating mutations in the CTNNB1 gene locus, or in the negative regulators AXIN and APC involving stabilization of ß-catenin, and activation of target genes leads to a more aggressive phenotype, suggesting its potential value as a therapeutic target in the treatment of pancreatic ductal adenocarcinoma. A number of small molecule and biologic agents have now been developed for targeting this pathway. This review summarizes the current knowledge about the therapeutic potential of targeting the Wnt pathway with particular emphasis on preclinical/clinical studies in the treatment of pancreatic ductal adenocarcinoma.

Association of a genetic variant in ATP-binding cassette sub-family B member 1 gene with poor prognosis in patients with squamous cell carcinoma of the esophagus.

Esophageal cancer is a common cause of death from cancer in men and the eighth most prevalent cancer globally. The morbidity and mortality rates are four times higher in men than in women. Genetic factors are among the susceptibility factors for squamous cell carcinoma of the esophagus. The rs2032582 polymorphism is a triallelic missense variant of the ABCB1 gene, that has been reported to be associated with several cancers. Here we have explored the association of the ABCB1 rs2032582 polymorphism with esophageal squamous cell carcinoma (ESCC) for the first time in a total of 251 subjects, with and without ESCC. Data from patient's record were obtained from the Mashhad University of Medical Sciences, and were used to recruit ESCC patients into the study. A total of 89 ESCC patients and 162 healthy controls were included. DNAs were extracted and genotyped using a TaqMan real-time PCR-based method. Caplan Meier method was applied to analyze patients overall survival, and progression-free survival and log-rank were used in order to compare the results. Logistic regression was used to calculate the association between risk of ESCC and different genotypes. Our data showed that patients with ESCC had a higher frequency of a T/A (TT/TA/AA) genotype for rs2032592 than individuals with GG-genotype. There were no associations between BMI and genotypic frequencies. Furthermore patients with TT/TA/AA genotypes had a poorer disease-free survival (P = 0.016) in comparison with GG genotype. We found a significant association of the ABCB1 rs2032582 polymorphism with prognosis, although further studies in a larger and multicenter setting are needed to value these findings. © 2019 IUBMB Life, 71(9):1252-1258, 2019.

The potential therapeutic and prognostic impacts of the c-MET/HGF signaling pathway in colorectal cancer.

Colorectal cancer (CRC) is the third most common cancer and a common cause of cancer-related mortality globally. In spite of the improvements in the early diagnosis of CRC, approximately one-third of patients develop metastasis and then have a very poor survival rate. The mesenchymal-epithelial transition factor (c-MET) is a tyrosine kinase cell surface receptor activated by hepatocyte growth factor (HGF). Activation of c-MET/HGF signaling pathway regulates a variety of biological processes including cell motility, cell proliferation, angiogenesis, the epithelial-to-mesenchymal transition, and the development and progression of cancer cells. Recent studies have suggested that the c-MET/HGF signaling pathway is involved in the carcinogenesis of CRC. In this review, we summarize the main findings of recent studies investigating the role of c-MET/HGF signaling pathway in CRC and the potential of the c-MET/HGF signaling pathways in the diagnosis and treatment of CRC. © 2019 IUBMB Life, 2019.

The prognostic and therapeutic application of microRNAs in breast cancer: Tissue and circulating microRNAs.

Breast cancer is the second most common malignancy diagnosed in women, supporting the need for identification of novel prognostic and diagnostic biomarkers. Recently, microRNAs have emerged as molecular regulators that can have key roles in pathogenesis and progression of different malignancies, including breast cancer. Micro-RNAs can be circulated in body fluid, suggesting their values as non-invasive marker. There is growing body of evidence showing the aberrant activation of some known circulating miRNAs, for example let-151a, miR-21, miR-155, miR-,145 miR-18a, miR-16 as well as tissue specific-miRNAs, for example miR-182, miR-145, miR-21, miR-155/154, miR-203, miR-213, miR-7 in patients affected by breast cancer. In addition, there is growing body of evidences on the value of miRNAs to be associated with drug-resistance, suggesting their values as a potential approach to overcome chemo-resistance. Attuned with these facts, this review highlights recent preclinical and clinical investigation performed on tissue-specific miRNAs and circulating as novel promising biomarkers for detection of patients at early stages, prediction of prognosis, and monitoring of the patients in response to therapy.

Therapeutic potential of novel formulated forms of curcumin in the treatment of breast cancer by the targeting of cellular and physiological dysregulated pathways.

Breast cancer is among the most important causes of cancer related death in women. There is a need for novel agents for targeting key signaling pathways to either improve the efficacy of the current therapy, or reduce toxicity. There is some evidence that curcumin may have antitumor activity in breast cancer. Several clinical trials have investigated its activity in patients with breast cancer, including a recent trial in breast cancer patients receiving radiotherapy, in whom it was shown that curcumin reduced the severity of radiation dermatitis, although it is associated with low bioavailability. Several approaches have been developed to increase its absorption rate (e.g., nano crystals, liposomes, polymers, and micelles) and co-delivery of curcumin with adjuvants as well as different conjugation to enhance its bioavailability. In particular, micro-emulsions is an option for transdermal curcumin delivery, which has been reported to increase its absorption. Lipid-based nano-micelles is another approach to enhance curcumin absorption via gastrointestinal tract, while polymer-based nano-formulations (e.g., poly D, L-lactic-co-glycolic [PLGA]) allows the release of curcumin at a sustained level. This review summarizes the current data of the therapeutic potential of novel formulations of curcumin with particular emphasis on recent preclinical and clinical studies in the treatment of breast cancer.

GD2-targeted immunotherapy and potential value of circulating microRNAs in neuroblastoma.

Neuroblastoma (NB) with various clinical presentation is a known childhood malignancy. Despite significant progress in treatment of NB afflicted patients, high risk disease is usually associated with poor outcome, resulting in long-term survival of less that 50%. Known as a disease most commonly originated form the nerve roots, the variants involved in NB imitation and progression remain to be elucidated. The outcome of low to intermediate risk disease is favorable whereas the high risk NB disease with dismal prognosis, positing the necessity of novel approaches for early detection and prognostication of advanced disease. Tailored immunotherapy approaches have shown significant improvement in high-risk NB patients. It has found a link between Gangliosides and progression of NB. The vast majority of neuroblastoma tumors express elevated levels of GD2, opening new insight into using anti-GD2 drugs as potential treatments for NBs. Implication of anti-GD2 monoclonal antibodies for treatment of high risk NBs triggers further investigation to unearth novel biomarkers as prognostic and response biomarker to guide additional multimodal tailored treatment approaches. A growing body of evidence supports the usefulness of miRNAs to evaluate high risk NBs response to anti-GD2 drugs and further prevent drug-related toxicities in refractory or recurrent NBs. miRNAs and circulating proteins in body fluids (plasma and serum) present as potential biomarkers in early detection of NBs. Here, we summarize various biomarkers involved in diagnosis, prognosis and response to treatment in patients with NB. We further attempted to overview prognostic biomarkers in response to treatment with anti-GD2 drugs.

The prognostic value of MGMT promoter methylation in glioblastoma: A meta-analysis of clinical trials.

The DNA repair protein O6-Methylguanine-DNA methyltransferase (MGMT) is suggested to be associated with resistance to alkylating agents such as Temozolomide which is being used in treatment of patients with glioblastoma (GBM). Therefore, we evaluated the associations between MGMT promoter methylation and prognosis of patients with glioblastoma (GBM). Data were extracted from publications in Embase, PubMed, and the Cochrane Library. Data on overall survival (OS), progression-free survival (PFS), and MGMT methylation status were obtained and 4,097 subjects were enrolled. Data from 34 studies showed that MGMT methylated patients had better OS, compared to GBM unmethylated patients (pooled HRs, 0.494; 95%CI 0.412-0.591; p = 0.001). Meta-analysis of 10 eligible studies reporting on PFS, demonstrated that MGMT promoter methylation was not significantly associated with better PFS (pooled HRs, 0.653; 95%CI 0.414-1.030; p = 0.067). GBM patients with MGMT methylation were associated with longer overall survival, although this effect was not detected for PFS. Moreover, we performed further analysis in patients underwent a comprehensive imaging evaluation. This data showed a significant association with better OS and PFS, although further studies are warranted to assess the value of emerging marker in prospective setting in patients with glioblastoma as a risk stratification biomarker in clinical management of the patients.

Genetic variation in the DNA repair pathway as a potential determinant of response to platinum-based chemotherapy in breast cancer.

Platinum-based chemotherapy is often used as a first-line treatment for patient with breast cancer. Platinum agents bind to DNA, forming adducts that contain intra and inter-strand crosslinks. It is possible that genetic variations of the DNA repair pathways may affect the activity, or efficacy of platinum, and hence resistance to platinum chemotherapy may be related to these genetic variants. We have summarized the known variants in the DNA repair pathway that have been reported to predict the response to platinum-based therapy in breast cancer.