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Gastric cancer (GC) is the second leading cause of cancer-related death worldwide, although its incidence in many Western countries declined during the last decade. Chemotherapy is widely used to treat GC, and a number of randomized studies have recently demonstrated that systemic treatment can improve overall survival (OS) or quality of life. However, expected survival for the advanced disease is generally poor (less than 1 year). A number of newer chemotherapeutic compounds have been studied intensively. These include taxanes, topoisomerase I inhibitors and oral fluoropyrimidines, as well as new biological agents aiming to inhibit or modulate different targets of signal-transduction pathways or angiogenesis. However, no active second-line therapy has demonstrated definitive clinical benefit in patients with advanced GC, and in some patients therapy results solely in severe, unpredictable toxicity without any tumor response. It is therefore crucial to individualize GC chemotherapy to allow the discernment of patients in whom a particular therapy will exert a real benefit.

In subgroups of gastric cancer patients, chemotherapy treatments carry a high risk of toxicity without any clear evidence of antitumor activity. Individualization of therapy is required to treat each patient with the optimal drug and dose. Genetic polymorphisms are the hereditary determinants for interindividual variations of drug effect and the genetic approach represents a new tool to design a tailored therapy. This review focuses on the relevance of the host polymorphisms involved in metabolism, cellular transport and interaction with molecular targets of the drugs used in gastric cancer in conventional or innovative chemotherapy regimens. Pharmacogenetic studies based on a single gene or multi-gene approach (pharmacogenomics) are promising to identify gastric cancer patients at risk for adverse toxicity, but larger and controlled studies are needed to justify changes in the chemotherapeutic strategies.

CYP1B1 is the enzyme with the highest efficiency of conversion of estradiol to 4-hydroxyestradiol in humans. This metabolite has a well-known carcinogenic effect interacting with genomic DNA and has been hypothesized to be partly responsible for the role played by estrogens in ovarian cancer development. A polymorphism has been described for this enzyme causing a Leu to Val substitution in position 432 (CYP1B1*3). The Val432 allele has a higher efficiency of conversion of estradiol to 4-hydroxyestradiol and has been reported to increase the risk of ovarian cancer. A previous study reported a higher, significant prevalence of CYP1B1*3 polymorphism in ovarian cancer patients of mixed ethnicity. The aim of this study was to investigate the role of CYP1B1*3 polymorphism as a risk factor for ovarian cancer in a Caucasian population. The polymorphism frequency was determined in 223 cases of ovarian cancer and compared with that of 280 healthy female blood donors. Genetic analysis was performed on genomic DNA from PBMC and RFLP methods were used for mutation detection. No significant difference between cases and controls was found. These results do not support a favoring role of CYP1B1*3 in ovarian cancer development in our population.

C677T and A1298C methylenetetrahydrofolate reductase (MTHFR) polymorphisms have been suggested to affect susceptibility to malignant lymphoma, possibly by altering DNA methylation. The DNA repair gene O6-methylguanine DNA methyltransferase (MGMT) is transcriptionally silenced by promoter hypermethylation in diffuse large B-cell lymphomas (DLBCL). We analyzed the MTHFR677 and MTHFR1298 genotypes in 111 DLBCL patients and 465 controls. No significant difference in the frequency of MTHFR polymorphisms between patients and controls and no significant association between MTHFR677 or MTHFR1298 genotypes and methylation of MGMT promoter were observed. These results indicate that MTHFR variants are not related to DLBCL development and MGMT hypermethylation.

Pharmacogenetics focuses on intersubjects variation in therapeutic drug effects and toxicity depending on genetic polymorphisms. This is particularly interesting in oncology since anticancer drugs usually have a narrow margin of safety. Irinotecan [7-ethyl-10-[4-(1-piperidino)-1-piperidino]carbonyloxycamptothecin] is used in cancer chemotherapy as a topoisomerase I inhibitor and it is characterised by a sometimes unpredictable severe toxicity. It is mostly intestinal with nausea, vomit and diarrhoea or haematologic with leuko-thrombocytopenia. Its complex metabolism involves many proteins. Human carboxylesterase isoforms 1 and 2 (hCE1, hCE2) activate irinotecan to its metabolite SN-38 (7-ethyl-10-hydroxycamptothecin); cytochrome P450 isoforms 3A4 and 3A5 (CYP3A4, CYP3A5) mediate the oxidation of the parental compound to irinotecan; uridino-glucuronosil transferase isoform 1A1 (UGT1A1) catalyses glucuronidation of SN-38; the multi-resistance protein isoform 2 (MRP2) allows the cellular excretion of the SN-38 glucuronide (SN-38G) and the multi-drug resistance gene (MDR1), encoding for P-glycoprotein, is responsible for the excretion of irinotecan from the cell. Polymorphic structures in the genes encoding for all these proteins have been described. In particular, the UGT1A1*28 allele has been associated with an increased toxicity after irinotecan chemotherapy. Classical parameters used in the clinic, such as body-surface area, have no longer a meaningful correlation with clinical outcome. Hence it emerges the importance of studying the individual genotype to predict the toxicity and efficacy of irinotecan and to individualise therapy. In this review, we summarise the new developments on the study of the pharmacogenetics of irinotecan, stressing its importance in drug cytotoxic effect.

The use of targeted agents in the treatment of metastatic colorectal cancer (CRC) has improved patient outcomes. Anti-epidermal growth factor receptor (anti-EGFR) agents (cetuximab and panitumumab) and antiangiogenic molecules (bevacizumab, regorafeninb, ramucirumab, and aflibercept) have been successfully integrated into clinical practice. Other drugs have been designed to target additional deregulated pathways in CRC, such as MAPK (mitogen-activated protein kinase)/PI3K-AKT (phosphatidylinositol-3-kinase-AKT serine/threonine kinase)/mTOR (mammalian target of rapamycin), HER-2 and 3 ( human epidermal growth factor receptor-2 and -3), and BRAF. A major issue with targeted treatment is early identification of patients with primary or secondary drug resistance. Pharmacogenomic research has demonstrated its value in this field, highlighting some tumor mutations that could discriminate responders from non-responders. The tumor genetic profile of the RAS/RAF pathway is needed before treatment with anti-EGFR agents; mutations in EGFR pathway genes have also been explored in relation to antiangiogenic molecules although further data are required prior to their integration into clinical practice. The introduction of immunotherapy has paved the way for a new generation of predictive markers, including genome-wide assessment of the tumor landscape. Furthermore, the development of next generation sequencing technology and non-invasive approaches to analyze circulating tumor DNA will make real-time monitoring of the tumor pharmacogenomic markers possible in the clinical routine, rendering precision medicine available to every patient.

Finasteride is a steroid 5-alpha-reductase inhibitor, approved for the treatment of androgenetic alopecia (AGA) and benign prostate hyperplasia. In some patients the treatment is associated with adverse side effects that could become persistent after therapy discontinuation, resulting in the so-called post-finasteride syndrome (PFS). A pharmacogenetic component in the response to finasteride treatment was previously demonstrated. Two polymorphisms (CAG) rs4045402 and (GGN) rs3138869 in the gene encoding for the androgen receptor (AR) have been hypothesized to play a role in finasteride sensitivity. We aimed to compare the rs4045402 and rs3138869 polymorphisms prevalence in a group of 69 selected subjects (AGA+PFS) that used finasteride to treat alopecia and developed persistent side effects, with that in a group of 91 untreated subjects with AGA (AGA), and a group of 76 untreated subjects without AGA (NO-AGA). The rs4045402 and rs3138869 polymorphisms extreme-lengths alleles were more frequent among AGA+PFS (odds ratio, 5.88; 95% CI, 1.87-18.52) and AGA subjects (odds ratio, 3.55; 95% CI, 1.13-11.21) than among NO-AGA subjects, probably reflecting the genetic predisposing factors for AGA development. In conclusion, we described a predictive effect of the less common repeats’ length CAG-rs4045402 and GGN-rs3138869 on AGA development. Prospective trials are required to confirm our findings also in other ethnicities, and to highlight possible further pharmacogenetic predictive markers of susceptibility to adverse effects.

Rs3814113 is the single-nucleotide polymorphism (SNP) showing the strongest association with high-grade serous ovarian carcinoma (HGSOC) incidence and is located in an intergenic region about 44 kb downstream of basonuclin 2 (BNC2) gene. Lifetime number of ovulations is associated with increased risk to develop HGSOC, probably because of cell damage of extrauterine Müllerian epithelium by ovulation-induced oxidative stress. However, the impact of low-penetrance HGSOC risk alleles (e.g. rs3814113) on the damage induced by oxidative stress remains unclear. Therefore, the purpose of this study was to investigate whether rs3814113 genetic interval regulates BNC2 expression and whether BNC2 expression levels impact on cell survival after oxidative stress. To do this, we analyzed gene expression levels of BNC2 first in HGSOC data sets and then in an isogenic cell line that we engineered to carry a 5 kb deletion around rs3814113. Finally, we silenced BNC2 and measured surviving cells after hydrogen peroxide (H2O2) treatment to simulate oxidative stress after ovulation. In this paper, we describe that BNC2 expression levels are reduced in HGSOC samples compared with control samples, and that BNC2 expression levels decrease following oxidative stress and ovulation in vitro and in vivo, respectively. Moreover, deletion of 5 kb surrounding rs3814113 decreases BNC2 expression levels in an isogenic cell line, and silencing of BNC2 expression levels increases cell survival after H2O2 treatment. Altogether, our findings suggest that the intergenic region located around rs3814113 regulates BNC2 expression, which in turn affects cell survival after oxidative stress response. Indeed, HGSOC samples present lower BNC2 expression levels that probably, in the initial phases of oncogenic transformation, conferred resistance to oxidative stress and ultimately reduced the clearance of cells with oxidative-induced damages.

In the last decade, genetic variations in ABC/SLC transporters and phase I/II enzymes have raised pharmacogenetic markers as being predictive to the attention of researchers in the field of personalized medicine in oncology. However, it is becoming evident that the sequence variations in these genes cannot address by themselves the sharp interindividual variability in drug effects. Recently, nuclear receptors (NRs), including pregnane X receptor, constitutive androstane receptor, retinoid X receptor, farnesoid X receptor, liver X receptor, vitamin D receptor, peroxisome proliferator-activated receptors and HNF4A, have demonstrated key roles in regulating transporter and metabolic gene expression in response to xeno/endobiotics, as well as antineoplastic drugs. These findings attracted interest to the genetics of the NRs for their possible role in influencing the metabolism and pharmacological profiles of chemotherapeutics. In this review, we aim to summarize the most recent findings in the innovative field of NR pharmacogenetics and findings in how they could integrate with more traditional markers in order to improve drug treatment personalization.

Membrane transporters are widely recognized as important determinants of drug disposition and response, generating increasing interest on the pharmacological implications of their genetic variations. The aim of this study was to elucidate the predictive/prognostic role of ATP-binding cassette (ABC) and solute carrier (SLC) protein polymorphisms on irinotecan (FOLFIRI regimen) outcome.A total of 250 White metastatic colorectal cancer patients homogenously treated with a first-line FOLFIRI regimen were genotyped for a panel of variants in five transporter genes. The primary study endpoints were the response rate (partial or complete response), overall survival, and time to progression. Toxicity was considered a secondary endpoint. Irinotecan pharmacokinetic data of 71 patients were used for polymorphism functional analysis.Two variants of the ABCG2 (-15622CT, rs7699188) gene were found to be predictive (P0.01) of the response rate. High-order relationships of ABC/SLC markers with previously investigated genetic (UGT1A1 polymorphisms) and nongenetic (primary tumor site) factors that helped determine the response rate were highlighted. A prognostic effect of the ABCB1 rs2032582 variant on patient overall survival emerged (P = 0.0074). The ABCG2 rs7699788 variant was also seen to be associated with grade 3-4 nonhematological toxicity (P = 0.0012). The ABCG2 (-15622CT, rs7699188) and ABCB1 (rs2032582) polymorphisms were not found to be associated with pharmacokinetic parameters.This study showed that ABC/SLC polymorphisms have a crucial contribution toward the FOLFIRI outcome. This could represent a further step toward personalized therapy.

The discovery of pharmacogenomic markers in colorectal cancer (CRC) could be setting-specific. FOLFOX4 is employed in the adjuvant and metastatic setting in CRC. This prospective study is aimed to validate in the adjuvant setting the pharmacogenomic markers of toxicity reported in the metastatic setting (that is, GSTP1-rs947894, and -rs1138272; GSTM1-null genotype; AGXT-rs4426527, -rs34116584 and del-74 bp), and to discover additional markers. CRC patients (n = 144) treated with adjuvant FOLFOX4 were genotyped for 57 polymorphisms in 29 genes. Grade ≥2 neurotoxicity was associated false discovery rate-adjusted q-value

The aim of the study was the identification of a pharmacogenetic profile predictive of the tumor regression grade (TRG), considered as tumor response parameter, after neo-adjuvant treatment in rectal cancer patients. A total of 238 rectal cancer patients treated in a neo-adjuvant setting by a fluoropyrimidines-based chemo-radiotherapy (RT) were genotyped for 25 genetic polymorphisms in 16 genes relevant for treatment-associated pathways. Two polymorphisms were associated with TRG in a multivariate analysis: hOGG1-1245C>G, which can affect radiosensitivity and MTHFR-677C>T, which is involved in fluoropyrimidines action. Patients bearing at least one variant allele had a lower chance to get TRG T, which is responsible for the multi-drug resistance (odds ratio (OR)=1.96, 95% confidence interval (CI) 0.98-3.95, P=0.057). Exploratory classification and regression tree (CART) analysis highlighted high-order gene-gene and gene-environment interactions and a genetic signature associated with differential response, with hOGG1-1245C>G as the most predictive factor. Other significant variables were: ABCB1-3435C>T, MTHFR-677C>T, ERCC1-8092C>A, ABCC2-1249G>A, XRCC1-28152G>A, XRCC3-4541A>G and patients gender. On the basis of CART results, patients were categorized into three groups according to tumor response probability: intermediate and high profiles had a higher probability to get TRG G and MTHFR-677C>T polymorphisms in the tumor response of rectal cancer patients treated with chemo-RT in neo-adjuvant setting, and shows the relevance of gene-gene and gene-environment interactions for complex phenotypes as tumor response. The Pharmacogenomics Journal (2011) 11, 214-226; doi:10.1038/tpj.2010.25; published online 6 April 2010

Two common mutations, 677 C--T and a1298 A--C, in the methylenetetrahydrofolate reductase gene (MTHFR) reduce the activity of MTHFR and folate metabolism. Familial aggregation in a variable but significant proportion of gastric cancer (GC) cases suggests the importance of genetic predisposition in determining risk. In this study, we evaluate MTHFR polymorphisms in 57 patients with a diagnosis of GC, in 37 with a history of GC in first-degree relatives (GC-relatives), and in 454 blood donors. Helicobacter pylori (HP) infection was also determined. An increased risk was found for 677TT in GC patients with respect to blood donors (odds ratio (OR) = 1.98), and statistical significance was sustained when we compared sex-age-matched GC patients and donors (OR = 2.37). The 677TT genotype association with GC was found in women (OR = 3.10), while a reduction in the 667C allele frequency was present in both the sex. No statistically significant association was detected when 677-1298 genotype was stratified by sex and age. Men of GC-relatives showed a higher 1298C allele frequency than donors (OR = 4.38). Between GC and GC-relatives, HP infection frequency was similar. In conclusion, overall findings support the hypothesis that folate plays a role in GC risk. GC-relatives evidence a similar 677TT frequency to that found in the general population.

Background: Genotyping is crucial for the identification of genetic markers underlying the development of neoplastic diseases and for determining individual variations in response to specific drugs. Technologies which can accurately identify genetic polymorphisms will dramatically affect routine diagnostic processes and future therapeutic developments in personalized medicine. However, such methods need to fulfill the principles of analytical validation to determine their suitability to assess nucleotide polymorphisms in target genes. Approach: This article reviews recent developments in homogeneous technologies for the genotyping of single nucleotide polymorphisms. Here, homogeneous methods essentially refer to “single-tube” assays performed in a liquid phase. For the appropriate choice of any method, several criteria must be considered: 1) detection of known genetic variations; 2) analytical performance including specificity, sensitivity and robustness of the method; 3) availability of large platforms and required equipment; 4) suitability of platforms and tests for routine diagnostics; 5) suitability for high throughput implementation. Content: This review is intended to provide the reader with an understanding of these various technologies for pharmacogenomic testing in the routine clinical laboratory. A brief overview is provided on the available technologies for the detection of known mutations, a specific description of the homogeneous platforms currently employed in genotyping analysis, and considerations regarding the proper assessment of the analytical performance of these methods. Based on the criteria proposed here, potential users may evaluate advantages and limitations of the various analytical platforms and identify the most appropriate platform according to their specific setting and diagnostic needs. Clin Chem Lab Med 2010;48:447–59.

Purpose We aimed to identify the maximum-tolerated dose (MTD) of irinotecan in patients with cancer with UGT1A1*1/*1 and *1/*28 genotypes. We hypothesize that the patients without the *28/*28 genotype tolerate higher doses of irinotecan. Patients and Methods Patients undergoing first-line treatment for metastatic colorectal cancer (CRC) eligible for treatment with irinotecan plus infusional fluorouracil/leucovorin (FOLFIRI) were screened for the UGT1A1*28/*28 genotype and excluded from the study. Fifty-nine white patients with either the *1/*1 or the *1/*28 genotype were eligible for dose escalation of irinotecan. The starting dose of biweekly irinotecan was 215 mg/m2 for both genotype groups, whereas the dose of infusional fluorouracil was fixed. Pharmacokinetic data of irinotecan and metabolites were also obtained. Results The dose of irinotecan was escalated to 370 mg/m2 in patients with the *1/*28 genotype and to 420 mg/m2 in those with the *1/*1 genotype. Dose-limiting toxicities (DLTs) were observed in two of four of *1/*28 patients at 370 mg/m2 and in two of three of *1/*1 patients at 420 mg/m2. No DLTs were observed in 10 *1/*28 patients at 310 mg/m2 and in 10 *1/*1 patients at 370 mg/m2; hence these dose levels were the MTD for each genotype group. The most common grade 3 to 4 toxicities were neutropenia and diarrhea. The pharmacokinetics of irinotecan and SN-38 exhibit linear kinetics. Conclusion The recommended dose of 180 mg/m2 for irinotecan in FOLFIRI is considerably lower than the dose that can be tolerated when patients with the UGT1A1*28/*28 genotype are excluded. Prospective genotype-driven studies should test the efficacy of higher irinotecan doses in the FOLFIRI schedule.

Purpose: The germ-line polymorphisms TP53 Arg72Pro and MDM2 SNP309 T>G are risk factors for tumor development and affect response to chemotherapy and survival in several cancers, but their prognostic and predictive value in patients with high-grade osteosarcomas is not yet defined. The purpose of this study was to investigate the effect of the TP53 Arg72Pro and the MDM2 SNP309 on the risk of osteosarcoma development and survival. Experimental Design: The relative risk to develop osteosarcomas and the overall survival associated to TP53 Arg72Pro and MDM2 SNP309 polymorphisms were investigated in 201 patients. Correlations with event-free survival (EFS) were analyzed in a homogeneous subgroup of 130 patients with high-grade osteosarcomas of the limbs, nonmetastatic at diagnosis, which underwent neoadjuvant chemotherapy. Results: Multivariate analysis showed that the MDM2 polymorphism T309G was associated with an increased risk of developing osteosarcomas [GG versus TT; odds ratio, 2.09; 95% confidence interval (95% CI), 1.15-3.78]. A case/control gender approach evidenced a significant increased risk only for female osteosarcoma patients (GG versus TT; odds ratio, 4.26; 95% CI, 1.61-11.25). Subjects carrying the TP53 Arg72Pro polymorphism were found to have a significantly increased death risk (Pro/Pro versus Arg/Arg; hazard ratio, 2.90; 95% CI, 1.28-6.66). In the subgroup of 130 high-grade osteosarcomas, the TP53 Arg72Pro was an independent marker of EFS (Pro/Pro versus Arg/Arg; hazard ratio, 2.67; 95% CI, 1.17-6.11). Conclusion: The study provides evidence supporting the association of MDM2 SNP309 with high-grade osteosarcoma risk in females and shows that TP53 Arg72Pro has a prognostic value for overall survival and EFS in osteosarcoma patients.

Purpose UGT1A1★28 is considered the main pharmacogenetic predictor of the toxicity outcome of irinotecan-treated patients. We evaluated the effect of other UGT1A variants and haplotypes involved in 7-ethyl-10-hydroxycamptothecin (SN-38) glucuronidation on severe toxicity and efficacy of fluorouracil, leucovorin, and irinotecan (FOLFIRI). Patients and Methods In addition to UGT1A1★28, UGT1A1★60, UGT1A1★93, UGT1A7★3, and UGT1A9★22 were genotyped in 250 metastatic colorectal cancer patients, and associations with severe hematologic and nonhematologic toxicity, objective response, time to progression (TTP), and overall survival were evaluated. In a subset of 71 patients, pharmacokinetic data were also available. Results UGT1A7★3 was the only marker of severe hematologic toxicity after the first cycle (odds ratio [OR], 3.94; 95% CI, 1.05 to 14.82; P = .04) in a multivariate analysis. It was also associated with glucuronidation ratio (SN-38G area under the curve [AUC]/SN-38 AUC) and biliary index (irinotecan AUC) × (SN-38 AUC/SN-38G AUC). Haplotype I (all the reference sequence alleles but UGT1A9★22) was a predictor of severe hematologic toxicity during the entire course of therapy (OR, 0.39; 95% CI, 0.19 to 0.82; P = .01), together with sex (OR, 2.08; 95% CI, 1.01 to 4.28; P = .05). In addition to UGT1A1★28, haplotype II (all the variant alleles but UGT1A9★22) was associated with a response rate (OR, 8.61; 95% CI, 1.75 to 42.38; P = .01). UGT1A1★28 was the only marker associated with TTP. Conclusion We propose that UGT1A variants additional to UGT1A1★28 might improve the prediction of the outcome of colorectal cancer patients treated with FOLFIRI. A UGT1A haplotype-based approach might be an efficacious strategy to achieve treatment individualization of FOLFIRI.

Research into the molecular bases of malignant diseases has yielded the development of many novel agents with potential antitumor activity. Evidence for a causative role for the epidermal growth factor receptor (EGFR), which is now regarded as an excellent target for cancer chemotherapy in human cancer, leads to the development of EGFR inhibitors. Two classes of anti-EGFR agents are currently in clinical use: monoclonal antibodies directed at the extracellular domain of the receptor, and the low-molecular-weight receptor tyrosine kinase inhibitors acting intracellularly by competing with adenosine triphosphate for binding to the tyrosine kinase portion of the EGFR. The effect on the receptor interferes with key biological functions including cell cycle arrest, potentiation of apoptosis, inhibition of angiogenesis and cell invasion and metastasis. Cetuximab, a monoclonal antibody, and the receptor tyrosine kinase inhibitors gefitinib and erlotinib are currently approved for the treatment of patients with cancer. New agents with clinical activity are entering the clinic, and new combinatorial approaches are being explored with the aim of improving the potency and pharmacokinetics of EGFR inhibition, to increase the synergistic activity in combination with chemotherapy and overcome resistance to the EGFR inhibitors.

Although new drugs and association regimens have been used in recent years, the chemotherapeutic outcome for gastric cancer is still poor and improvement in patient survival is not satisfactory. Pharmacogenetics could represent a useful approach to optimize chemotherapeutic treatments in order to identify individuals that are true candidates for clinical benefits from therapy, avoiding the development of severe side effects. The most recent update regarding gastric cancer pharmacogenetics highlights a prominent role of genetic polymorphisms of thymidylate synthase and glutathione S-transferase in the pharmacological treatment with commonly used drugs, such as 5-fluorouracil and platinum derivatives. In order to validate the genetic markers, further larger scale and controlled studies are required. A future challenge is represented by the introduction of targeted therapy in gastric cancer treatment, with the potential emerging tool of pharmacogenetic impact on this field.

Purpose: Irinotecan (CPT11) is a prodrug activated in humans mainly by carboxylesterase 2 (CES2) generating the SN38 metabolite responsible for the drug efficacy and toxicity. The interpatients variability in CPT11 activation step could cause unpredictable toxicity. To identify a predictive molecular marker for CPT11 activation in cancer patients, we investigated the CES2 mRNA expression in peripheral blood mononuclear cells (PBMC) and correlated it to CPT11 activation rate, toxic effects, and response.Experimental Design: Forty-five colorectal cancer patients were treated with a CPT11-including regimen (FOLFIRI). CES2 mRNA expression in PBMC was quantified by reverse transcription-PCR in real time. Plasma concentrations of CPT11, SN38, and SN38-glucuronide were determined by high-performance liquid chromatography and the pharmacokinetic variables calculated adopting the noncompartmental model. Toxicity was evaluated by the National Cancer Institute Common Toxicity Criteria scale and response by the WHO criteria.Results: A high interindividual variability in CES2 mRNA relative expression was observed (median, 1.45; range, 0.01-28.21). CES2 mRNA expression level was significantly associated with CPT11 activation ratio [(AUCSN38 + AUCSN38G)/AUCCPT11]. Patients with CES2 mRNA expression above the median cutoff value presented an activation ratio higher (median, 0.25; range, 0.15-0.42) than those with CES2 mRNA below the median (median, 0.20; range, 0.10-0.40; P = 0.013). This was associated with a nonsignificant trend of 1.34-fold increase of SN38 AUC in the group of patients with high CES2 mRNA expression (mean, 1.03 ± 0.62 versus 0.77 ± 0.32 μmol/L hour). Eight of 23 high CES2 mRNA–expressing patients (34.8%) developed grade 3 to 4 neutropenia or diarrhea compared with 2 of 22 (9.1%) in the low CES2-expressing group (P = 0.071).Conclusion: Our data support a predictive power of CES2 mRNA expression in PBMC for the activation rate of CPT11.

(Uridino-diphosphate)glucuronosyl-transferase enzyme 1A1 isoform (UGT1A1) is involved in glucuronidation of antineoplastic drugs such as SN38, the active metabolite of irinotecan, as well as estrogens and their metabolites. UGT1A1*28 polymorphism decreases UGT1A1 expression and could alter estrogens disposition influencing tumour growth in hormone sensitive tissues. The UGT1A1*28 distribution among an ovarian cancer patient (OCP) population of 217 mono-institutional individuals was investigated to clarify its possible involvement in the pathogenesis and chemotherapy of ovarian cancer. Data were compared with those of 205 female healthy blood donors. In 160 patients also the tumour tissue was genotyped to describe the occurrence of loss of heterozygosity (LOH). A PCR based assay followed by automated fragment analysis was used. Odds ratios (OR), and 95% confidence intervals (95% CI), were computed by a multiple logistic regression model using as dependent variable in a case-control or in a case-case approach the histological classification. No significant prevalence of the polymorphism was observed in the cases versus controls. In a case-case approach, a higher frequency of the polymorphism was observed in patients with mucinous tumours (6/11, 54.6%) compared to non-mucinous (30/206, 14.6%) (p=0.009, OR=7.20; 95% CI 2.06-25.19). LOH was observed in 12 cases out of 160 (7.5%) and was associated with non-mucinous tumours, 10 (83.3%) cases determined a retention of the wild-type allele. In conclusion, the prevalence of UGT1A1*28 found in mucinous OCP could suggest a role in the development of specific histologic sub-groups and could become a marker to be considered when planning ovarian cancer chemotherapy.

Conventionally adjustments of the dose of chemotherapeutic treatment could be uneffective in preventing toxicity and response variability. New strategies for individualization of treatment in cancer patients are becoming an emerging issue in the clinical practice. Pharmacogenetics is undoubtedly an important source of information in this respect deepening the complex correlation existing between individual genetic profile and the response to therapy in terms of toxicity and activity. Several polymorphisms, i.e. genetic mutations with a frequency1% in a given population, have been described for genes encoding proteins involved in the metabolism of the drugs employed in the treatment of gastric cancer. TS (thymidilate synthase) and DPD (dihydropyrimidine dehydrogenase) polymorphisms are implicated in the development of toxicity and in the efficacy of 5-fluorouracil (5FU). XRCC1 (X-ray cross-complementing group 1), ERCC1 (excision cross-complementing gene) and GSTP1 (glutathione S-transferase) have a role in the development of pharmacoresistance to platinum derivatives. MTHFR (5, 10 methylenetetrahydrofolate reductase) C677T polymorphism is important in methotrexate (MTX) metabolism. UGT1A1 (uridine diphoshate-glucuronosyltransferase 1A1) is involved on irinotecan metabolism. MRP2 (multi-drug resistance associated protein) and MDR1 (multi-drug resistance gene) are involved in irinotecan as well as anthracyclines transport. In conclusion, the clinical applications of pharmacogenetics could represent a new insight to accurately determine the proper drug and dose to be used in each individual patient.

Introduction: Colorectal cancer (CRC) remains a significant cause of mortality accounting for 10% of all deaths of malignancies in European Caucasians. Glutathione S-transferases (GSTs) participate in the detoxification of chemotherapeutic agents used in therapy of CRC. Genetic polymorphisms in GST genes (copy-number variants of GSTM1 and GSTT1) that lead to diminished enzyme activity have been associated with CRC risk and survival increased chemotherapeutic treatment benefit in patients in most of the studies. Aims: In this study we examined associations of GSTM1 and GSTT1 genotypes and clinical factors (age, gender, stage, localization of the tumor) with risk and we assessed the effect of genetic polymorphisms in GST genes on survival in CRC patients treated with adjuvant/palliative chemotherapy. Materials & methods: We followed 1106 CRC patients treated with chemotherapy based on fluoropyrimidines and 1343 unrelated controls. Polymorphisms were genotyped by a relative quantification method (copy-number variants of GSTM1 and GSTT1), and PCR followed by gel electrophoresis (null/non-null genotypes for GSTM1 and GSTT1). Statistical evaluations of risk were evaluated using the Pearson Chi-Square Test. Associations between genotypes and overall survival were assessed using Kaplan-Meier curves and Cox proportional hazards regression. Results: GSTT1 null was associated with a small but significant increase in risk (p = 0.013, OR = 1.393, 95% CI = 1.007-1.818). Copy-number variants of GSTM1 was associated with a reduction of risk (pDominant model < 0.001, OR = 0.673, 95% CI = 0.552-0.820). The same associations were founded in male cases after gender stratification. There were no significant associations between GSTT1 and GSTM1 genotypes with other clinical factors (localization, stage and tumor node metastasis classification) in the total case group. However, following stratification by age ( Furthermore, GSTM1 null and GSTT1 copy number variation were associated with low survival rates in younger patients (p = 0.047, HR = 3.937; p = 0.039, HR = 4.246). However, survival increase is observed in young patients with GSTM1 copy number variant (pDominant model < 0.001, HR = 13.246). Conclusions: This study confirms the association with the risk and the effect of GSTT1 and GSTM1 polymorphisms on survival in CRC patients who received chemotherapy. We also suggest a specific risk association with GST null genotype in younger patients, particularly in those with presentation of tumor under the age of 70 years. The null GST genotype could be related to an improved immune response in younger patients, but less detoxification and increased rates of DNA damage in older patients. Citation Format: Silvia Boffo, Erika Cecchin, Flavio Rizzolio, Sara Lonardi, Vittorina Zagonel, Pasquale Fiduccia, Giuseppe Toffoli. GSTM1 and GSTT1 polymorphisms in population-based study of colorectal cancer risk. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4841. doi:10.1158/1538-7445.AM2013-4841

In Response: The primary aim of our report was to describe and validate a measurable molecular variable that could explain the metabolic conversion of irinotecan (CPT11) to SN38, the pharmacologically active metabolite which exerts chemotherapeutic and toxic effects. In particular, expression of

Pharmacogenetics could be a useful tool for performing tailored anticancer chemotherapy. Several polymorphisms potentially affecting enzymes responsible for metabolism, transport and mechanism of action of irinotecan, fluoropyrimidines and antifolate agents have been investigated and sometimes associated with toxicity and response. In particular, uridine diphosphoglucuronosyl transferase 1A1 (UGT1A1) enzyme is responsible for detoxification of irinotecan active metabolite, SN38. A polymorphic structure in the promoter region (UGT1A1*28) may affect irinotecan toxicity and SN38 plasma level. Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme in the folate cycle, presenting two common polymorphisms (677C>T and 1298 A>C) which have impact on toxicity and efficacy of methotrexate and 5-fluorouracil.

Neoadjuvant chemoradiotherapy (nCRT) followed by radical surgery is the standard of care for patients with Locally Advanced Rectal Cancer (LARC). Current selection for nCRT is based on clinical criteria regardless of any molecular marker. Pharmacogenomics may be a useful strategy to personalize and optimize nCRT in LARC. This review aims to summarize the most recent and relevant findings about the role of germline and somatic pharmacogenomics in the prediction of nCRT outcome in patients with LARC, discussing the state of the art of their application in the clinical practice. A systematic literature search of the PubMed database was completed to identify relevant English-language papers published up to January 2020. The chemotherapeutic backbone of nCRT is represented by fluoropyrimidines, mainly metabolized by DPD (Dihydro-Pyrimidine Dehydrogenase, DPYD). The clinical impact of testing DPYD*2A, DPYD*13, c.2846A > T and c.1236G > A-HapB3 before a fluoropyrimidines administration to increase treatment safety is widely acknowledged. Other relevant target genes are TYMS (Thymidylate Synthase) and MTHFR (Methylene-Tetrahydro-Folate Reductase), whose polymorphisms were mainly studied as potential markers of treatment efficacy in LARC. A pivotal role of a TYMS polymorphism in the gene promoter region (rs34743033) was reported and was pioneeringly used to guide nCRT treatment in a phase II study. The pharmacogenomic analysis of other pathways mostly involved in the cellular response to radiation damage, as the DNA repair and the activation of the inflammatory cascade, provided less consistent results. A high rate of somatic mutation in genes belonging to PI3K (Phosphatidyl-Inositol 3-Kinase) and MAPK (Mitogen-Activated Protein Kinase) pathways, as BRAF (V-raf murine sarcoma viral oncogene homolog B1), KRAS (Kirsten Rat Sarcoma viral oncogene homolog), NRAS (Neuroblastoma RAS viral (v-ras) oncogene homolog), PIK3CA (Phosphatidyl-Inositol-4,5-bisphosphate 3-Kinase, Catalytic Subunit Alpha), as well as TP53 (Tumor Protein 53) was reported in LARC. Their pharmacogenomic role, already defined in colorectal cancer, is under investigation in LARC with promising results concerning specific somatic mutations in KRAS and TP53, as predictors of tumor response and prognosis. The availability of circulating tumor DNA in plasma may also represent an opportunity to monitor somatic mutations in course of therapy.

Locally advanced rectal cancer (RC) treatment is a challenge, because RC has a high rate of local recurrence. To date preoperative chemoradiotherapy (pCRT) is widely accepted as standard protocol of care for middle-low RC, but complete tumour response rate ranges from 4 to 44% and 5-year local recurrence rate is 6%. Better understanding of molecular biology and carcinogenesis pathways could be used both for pre-neoplastic lesions and locally recurrence diagnosis, and for tumour response prediction to therapy. Circulating molecules, gene expression and protein signature are promising sources to biomarker discovery. Several studies have evaluated potential predictors of response and recently, cell-free Nucleic Acid levels have been associated to tumour response to neoadjuvant therapies. Alternative method is the serum or plasma proteome and peptidome analysis. It may be ideally suited for its minimal invasiveness and it can be repeated at multiple time points throughout the treatment in contrast to tissue-based methods which still remain the most reliable and specific approach. Many studies have analyzed preoperative rectal tissue prognostic factor, but data are controversial or not confirmed.