Global assessment of genetic variation influencing response to retinoid chemoprevention in head and neck cancer patients

Onco-Ontogeny of Squamous Cell Cancer of the First Pharyngeal Arch Derivatives

Head and neck squamous cell carcinoma (H&NSCC) is an anatomic, biological, and genetic complex disease. It involves more than 1000 genes implied in its oncogenesis; for this review, we limit our search and description to the genes implied in the onco-ontogeny of the derivates from the first pharyngeal arch during embryo development. They can be grouped as transcription factors and signaling molecules (that act as growth factors that bind to receptors). Finally, we propose the term embryo-oncogenesis to refer to the activation, reactivation, and use of the genes involved in the embryo's development during the oncogenesis or malignant tumor invasion and metastasis events as part of an onco-ontogenic inverse process.

Chemoprevention of oral cancer: A review and future perspectives

BACKGROUND

Oral cancer causes significant morbidity and mortality. Chemoprevention utilizes medication or natural compounds to reverse oral premalignant lesions and to prevent second primary tumors.

METHODS

A comprehensive PubMed database and Cochrane Library search from 1980 to 2021 was performed using the keywords "leukoplakia," "oral premalignant lesion," and "chemoprevention."

RESULTS

Chemopreventive agents included retinoids, carotenoids, cyclooxygenase inhibitor, herbal extracts, bleomycin, tyrosine kinase inhibitors, metformin, and immune checkpoint inhibitors. Although some agents demonstrated effect in reducing premalignant lesions and preventing second primary tumors, the results among different studies were highly variable.

CONCLUSIONS

The results of different trials, albeit inconsistent, provided substantial information for future studies. In the era of personalized medicine, future studies will focus on identifying specific biomarkers and molecular profile to monitor and to prevent malignant transformation. Larger trials are warranted to validate the effect of chemopreventive agents.

Complementary and Integrative Medicine in Head and Neck Cancer

Complementary/integrative medicine (CIM) is an evolving area of collaboration between oncology, patient and their beliefs, and practitioners of complementary medicine. Evidence-informed decision-making is necessary to advise patients on which treatments may be incorporated into standard of care treatments for cancer. Patients use CIM for a variety of reasons and often have unrealistic expectations of cure or disease modifications; on the other hand, there is increasing evidence that symptoms, side effects, and dysfunction related to cancer and its treatment can be ameliorated by CIM approaches to improve patient satisfaction and quality of life. Open communication between patients and providers is paramount.

Pharmacogenetics in Neuroblastoma: What Can Already Be Clinically Implemented and What Is Coming Next?

Pharmacogenetics is one of the cornerstones of Personalized Precision Medicine that needs to be implemented in the routine of our patients' clinical management in order to tailor their therapies as much as possible, with the aim of maximizing efficacy and minimizing toxicity. This is of great importance, especially in pediatric cancer and even more in complex malignancies such as neuroblastoma, where the rates of therapeutic success are still below those of many other types of tumors. The studies are mainly focused on germline genetic variants and in the present review, state of the art is presented: which are the variants that have a level of evidence high enough to be implemented in the clinic, and how to distinguish them from the ones that still need validation to confirm their utility. Further aspects as relevant characteristics regarding ontogeny and future directions in the research will also be discussed.

Retinoids as Chemo-Preventive and Molecular-Targeted Anti-Cancer Therapies

Retinoic acid (RA) agents possess anti-tumor activity through their ability to induce cellular differentiation. However, retinoids have not yet been translated into effective systemic treatments for most solid tumors. RA signaling is mediated by the following two nuclear retinoic receptor subtypes: the retinoic acid receptor (RAR) and the retinoic X receptor (RXR), and their isoforms. The identification of mutations in retinoid receptors and other RA signaling pathway genes in human cancers offers opportunities for target discovery, drug design, and personalized medicine for distinct molecular retinoid subtypes. For example, chromosomal translocation involving RARA occurs in acute promyelocytic leukemia (APL), and all-trans retinoic acid (ATRA) is a highly effective and even curative therapeutic for APL patients. Thus, retinoid-based target discovery presents an important line of attack toward designing new, more effective strategies for treating other cancer types. Here, we review retinoid signaling, provide an update on retinoid agents and the current clinical research on retinoids in cancer, and discuss how the retinoid pathway genotype affects the ability of retinoid agents to inhibit the growth of colorectal cancer (CRC) cells. We also deliberate on why retinoid agents have not shown clinical efficacy against solid tumors and discuss alternative strategies that could overcome the lack of efficacy.

Single nucleotide polymorphisms and the risk of developing a second primary cancer among head and neck cancer patients: a systematic literature review and meta-analysis

BACKGROUND

Head and Neck Cancer (HNC) survivors are at increased risk of developing a second primary cancer (SPC). Along with the environmental risk factors, genetic factors have been associated with a potential increased susceptibility to SPC development. We aim to identify the Single Nucleotide Polymorphisms (SNPs) that contribute to SPC development among HNC survivors through a systematic review and meta-analysis.

METHODS

We searched PubMed, Scopus and ISI Web of Science for eligible studies published in English until January 31st, 2020. We included studies reporting primary data that evaluated the association between SNPs and SPC risk in HNC patients. Data were pooled in a random-effect meta-analyses, when at least two studies on the same SNP evaluated the same genotype model. Heterogeneity was assessed using the χ2-based Q-statistics and the I2 statistics. Quality of the included studies was assessed using the Q-Genie tool.

RESULTS

Twenty-one studies, of moderate to good quality, were included in the systematic review. Fifty-one genes were reported across the included studies to have significant associations with an increased SPC risk. Overall, 81 out of 122 investigated SNPs were significantly associated with the SPC risk. Seven studies were included in the meta-analysis, which showed five SNPs associated with an increased risk of SPC: p21C70T, CT + TT (HR = 1.76; 95% CI: 1.28-2.43); FASLG -844C > T, CT + TT (HR = 1.82; 95% CI: 1.35-2.46), P21 C98A, CA + AA (HR = 1.75; 95% CI: 1.28-2.38); FAS -670A > G (HR = 1.84; 95% CI: 1.28-2.66) and GST-M1, Null genotype (HR = 1.54; 95% CI: 1.13-2.10).

CONCLUSIONS

The identified SNPs in our systematic review and meta-analysis might serve as potential markers for identification of patients at high risk of developing SPC after primary HNC.

PROSPERO REGISTRATION NUMBER

CRD42019135612 .

Differences in Clinicopathological Characteristics and Prognosis Between Primary and Postirradiation Tongue Squamous Cell Carcinoma

PURPOSE

Many cases of postirradiation oral carcinoma have been reported, but its prognosis and optimal treatment modalities are not clear. Thus, the clinicopathologic characteristics and prognosis between postirradiation tongue squamous cell carcinoma (PTSCC) and primary tongue squamous cell carcinoma (TSCC) were compared.

PATIENTS AND METHODS

A retrospective cohort study was conducted to assess patients with PTSCC or TSCC. The primary predictor variable was tumor type. The primary outcome variable was prognosis, and the additional outcome variables were clinicopathologic characteristics. Survival analysis was performed, and Kaplan-Meier analysis was conducted to compare the effects of clinicopathologic factors on survival using SPSS 18.0. Moreover, the Cox model was applied in multivariate analysis.

RESULTS

The sample was composed of 449 patients with PTSCC (n = 68; 47 men and 21 women; age range, 31 to 72 yr) and TSCC (n = 381; 247 men and 134 women; age range, 20 to 86 yr). Patients with PTSCC were found to have a substantially poorer prognosis and several specific clinicopathologic characteristics compared with patients with TSCC.

CONCLUSION

Patients with PTSCC had several unique biological tumor characteristics and a poorer prognosis than patients with TSCC. Thus, different surgical strategies should be used to treat patients with PTSCC.

Effects of potentially functional polymorphisms in suppressor of cytokine signaling 3 (SOCS3) on the risk of head and neck squamous cancer

BACKGROUND

Suppressor of cytokine signaling 3 (SOCS3) has been identified as an inhibitor of JAK/STAT pathway that plays a significant role in carcinogenesis. SOCS3 and JAK2 polymorphisms may influence the gene expression or function, contributing to the disease susceptibility; however, such effect has not been evaluated in head and neck squamous cell carcinoma (HNSCC).

METHODS

A case-control study was performed to test the associations of SOCS3 and JAK2 polymorphisms with risk of HNSCC in 576 cases and 1552 cancer-free controls from China. Seven potentially functional polymorphisms predicted by bioinformatics tools were genotyped using Infinium BeadChip platform. The association between genotypes and HNSCC risk was estimated by computing odds ratios (ORs) and 95% confidence intervals (CIs) in univariate and multivariate logistic regression models.

RESULTS

We found that rs2280148 located at 3'-untranslated region of SOCS3 was significantly associated with an increased risk of HNSCC (additive model: adjusted OR = 1.21, 95% CI = 1.03-1.43, P = 0.021). Moreover, rs8064821 located in the promoter region of SOCS3 was linked with a decreased risk of the cancer (additive model: adjusted OR = 0.83, 95% CI = 0.71-0.97, P = 0.022). Combined analysis of these variants by the number of risk alleles showed a significant locus-dosage effect on the risk of HNSCC (P_trend = 0.006).

CONCLUSIONS

We provided the first evidence that SOCS3 polymorphisms may influence the risk of HNSCC, which could be applied as novel biomarkers to identify individuals at high risk of the disease.

Polymorphic variants in the vitamin D pathway genes and the risk of ovarian cancer among non-carriers of BRCA1/BRCA2 mutations

Previous studies have produced inconsistent results regarding the contribution of single-nucleotide polymorphisms (SNPs) in the vitamin D receptor (VDR) gene to ovarian cancer (OC) in various ethnicities. Additionally, little has been established with regard to the role of SNPs located in the retinoid X receptor α (RXRA), vitamin D-binding protein [also know as group-specific component (GC)] and VDR genes in non-carriers of the breast cancer 1/2 early onset (BRCA1/BRCA2) gene mutations. All participating individuals in the present study were evaluated for BRCA1 mutations (5382incC, C61G and 4153delA) with HybProbe assays, and for BRCA2 mutation (5946delT) using high-resolution melting (HRM) analysis. The associations of 8 SNPs located in RXRA, GC and VDR were investigated in OC patients without the BRCA1/BRCA2 mutations (n=245) and healthy controls (n=465). Genotyping of RXRA rs10881578 and rs10776909, and GC rs1155563 and rs2298849 SNPs was conducted by HRM analysis, while RXRA rs749759, GC rs7041, VDR BsmI rs1544410 and FokI rs2228570 genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism analysis. In addition, the gene-gene interactions among all tested SNPs were studied using the epistasis option in PLINK software. The lowest P-values of the trend test were identified for VDR rs1544410 and GC rs2298849 as P_trend=0.012 and P_trend=0.029, respectively. It was also found that, in the dominant inheritance model, VDR BsmI contributed to an increased risk of OC [odds ratio (OR), 1.570; 95% confidence interval (CI), 1.136-2.171; P=0.006; P_corr=0.048]. The gene-gene interaction analysis indicated a significant interaction between RXRA rs749759 and VDR FokI rs2228570 (OR for interaction, 1.687; χ²=8.278; asymptotic P-value=0.004; P_corr=0.032). In conclusion, this study demonstrated that certain VDR and RXRA SNPs may be risk factors for OC in non-carriers of BRCA1/BRCA2 mutations in the Polish population.

Molecular cancer prevention: Current status and future directions

The heterogeneity and complexity of advanced cancers strongly support the rationale for an enhanced focus on molecular prevention as a priority strategy to reduce the burden of cancer. Molecular prevention encompasses traditional chemopreventive agents as well as vaccinations and therapeutic approaches to cancer-predisposing conditions. Despite challenges to the field, we now have refined insights into cancer etiology and early pathogenesis; successful risk assessment and new risk models; agents with broad preventive efficacy (eg, aspirin) in common chronic diseases, including cancer; and a successful track record of more than 10 agents approved by the US Food and Drug Administration for the treatment of precancerous lesions or cancer risk reduction. The development of molecular preventive agents does not differ significantly from the development of therapies for advanced cancers, yet it has unique challenges and special considerations given that it most often involves healthy or asymptomatic individuals. Agents, biomarkers, cohorts, overall design, and endpoints are key determinants of molecular preventive trials, as with therapeutic trials, although distinctions exist for each within the preventive setting. Progress in the development and evolution of molecular preventive agents has been steadier in some organ systems, such as breast and skin, than in others. In order for molecular prevention to be fully realized as an effective strategy, several challenges to the field must be addressed. Here, the authors provide a brief overview of the context for and special considerations of molecular prevention along with a discussion of the results from major randomized controlled trials.

Retinoid Chemoprevention: Who Can Benefit?

Acute promyelocytic leukemia (APL) is a treatment success story. From a highly deadly disease it was turned into a highly curable disease by the introduction of differentiation-induction therapy with all-trans retinoic acid (ATRA) in the 1990's. During the last quarter of century, ATRA and other retinoids were used for the treatment and prevention of other cancers and even other diseases. The results were less spectacular, but nevertheless important. Progress has been made toward understanding the mechanism of action of retinoids in different physiological and pathological contexts. For some diseases, specific genetic backgrounds were found to confer responsiveness to retinoid therapy. Therapies that include retinoids and other modalities are very diverse and used both for combined targeting of multiple pathways and for diminishing toxicity.

Retinoic acid receptors: from molecular mechanisms to cancer therapy

Retinoic acid (RA), the major bioactive metabolite of retinol or vitamin A, induces a spectrum of pleiotropic effects in cell growth and differentiation that are relevant for embryonic development and adult physiology. The RA activity is mediated primarily by members of the retinoic acid receptor (RAR) subfamily, namely RARα, RARβ and RARγ, which belong to the nuclear receptor (NR) superfamily of transcription factors. RARs form heterodimers with members of the retinoid X receptor (RXR) subfamily and act as ligand-regulated transcription factors through binding specific RA response elements (RAREs) located in target genes promoters. RARs also have non-genomic effects and activate kinase signaling pathways, which fine-tune the transcription of the RA target genes. The disruption of RA signaling pathways is thought to underlie the etiology of a number of hematological and non-hematological malignancies, including leukemias, skin cancer, head/neck cancer, lung cancer, breast cancer, ovarian cancer, prostate cancer, renal cell carcinoma, pancreatic cancer, liver cancer, glioblastoma and neuroblastoma. Of note, RA and its derivatives (retinoids) are employed as potential chemotherapeutic or chemopreventive agents because of their differentiation, anti-proliferative, pro-apoptotic, and anti-oxidant effects. In humans, retinoids reverse premalignant epithelial lesions, induce the differentiation of myeloid normal and leukemic cells, and prevent lung, liver, and breast cancer. Here, we provide an overview of the biochemical and molecular mechanisms that regulate the RA and retinoid signaling pathways. Moreover, mechanisms through which deregulation of RA signaling pathways ultimately impact on cancer are examined. Finally, the therapeutic effects of retinoids are reported.

Pharmacogenomic analysis of retinoic-acid induced dyslipidemia in congenic rat model

Background

All-trans retinoic acid (ATRA, tretinoin) is a vitamin A derivative commonly used in the treatment of diverse conditions ranging from cancer to acne. In a fraction of predisposed individuals, the administration of ATRA is accompanied by variety of adverse metabolic effects, particularly by the induction of hyperlipidemia. We have previously derived a minimal congenic SHR.PD-(D8Rat42-D8Arb23)/Cub (SHR-Lx) strain sensitive to ATRA-induced increase of triacylglycerols and cholesterol under condition of high-sucrose diet. SHR-Lx differs only by 7 genes of polydactylous rat (PD/Cub) origin from its spontaneously hypertensive rat (SHR) progenitor strain.

Methods

Adult male rats of SHR and SHR-Lx strains were fed standard diet (STD) and experimental groups were subsequently treated with ATRA (15 mg/kg) via oral gavage for 16 days, while still on STD. We contrasted the metabolic profiles (including free fatty acids, triacylglycerols (TG) and cholesterol (C) in 20 lipoprotein fractions) between SHR and SHR-Lx under conditions of standard diet and standard diet + ATRA. We performed transcriptomic analysis of muscle tissue (m. soleus) in all groups using Affymetrix GeneChip Rat Gene 2.0 ST Arrays followed by Ingenuity Pathway Analysis and real-time PCR validation.

Results

In response to ATRA, SHR-Lx reacted with substantially greater rise in TG and C concentrations throughout the lipoprotein spectrum (two-way ANOVA strain * RA interaction significant for C content in chylomicrons (CM), VLDL and LDL as well as total, CM and HDL-TG).

Conclusions

According to our modeling of metabolic and signalization pathways using differentially expressed genes we have identified a network with major nodes (including Sirt3, Il1b, Cpt1b and Pparg) likely to underlie the observed strain specific response to ATRA.

Electronic supplementary material

The online version of this article (doi:10.1186/1476-511X-13-172) contains supplementary material, which is available to authorized users.

Clinical and prognostic analysis of second primary squamous cell carcinoma of the tongue after radiotherapy for nasopharyngeal carcinoma

We have investigated the clinical characteristics and prognostic factors of squamous cell carcinoma (SCC) of the tongue after definitive radiotherapy for nasopharyngeal carcinoma, and evaluated the effect of common therapeutic regimens for these patients. We retrospectively reviewed follow-up data for patients whose nasopharyngeal carcinoma had been treated by radiotherapy, and selected the 68 who had then developed SCC of the tongue, in the border of the tongue in half, and in the dorsum in 25 (37%). Eight of the 68 patients had clinical lymph node metastasis (12%), and 45 presented with stage I-II disease at the time of the diagnosis of the SCC (66%). Resection or radiotherapy alone was an effective treatment for patients with stage I-II SCC of the tongue, but patients with stage III-IV disease had a poor prognosis, despite being given multidisciplinary treatment. Multivariate analysis showed that the risk factors that independently influenced the survival of these patients were use of alcohol, recurrence of their nasopharyngeal carcinoma, the latency period, and the clinical TNM stage. Tongue SCC after radiotherapy was generally at an early stage and commonly occurred on the border or the dorsum of the tongue, with few lymph node metastases. Resection or radiotherapy is an effective treatment, and the risk factors that independently influenced the survival of patients indicate that improving the technique of radiotherapy and close follow-up after nasopharyngeal cancer are vitally important.

Protein marker profiling in different T classification in laryngeal squamous cell carcinoma

BACKGROUND

The identification of specific biomarkers related to laryngeal squamous cell carcinoma (SCC) will be helpful in early detection and determination of reasonable treatment options, which are crucial for the prognosis of patients with laryngeal SCC. The purpose of this study was to profile the protein markers that can be used for diagnosis and prognosis of laryngeal SCC and to observe laryngeal SCC progression with distinct stages of malignant transformation.

METHODS

Two hundred twenty-five proteins were tested in 84 pairs of tumors and adjacent nontumor mucosa samples using protein pathway arrays (PPAs). Ingenuity pathway analysis (IPA) enrichment analysis was performed and protein expression profiles in different T classification were mapped by grid analysis of time-series expression (GATE).

RESULTS

Among 16 proteins differently expressed between tumors and normal tissues, we selected 9 proteins (TTF-1, CDK2, Eg5, proliferating cell nuclear antigen [PCNA], Bcl-xL, 14-3-3β, p27, SRC-1, cytokeratin 18) as markers for classification. From the IPA analysis, we observed a more malignant transformation from T3 to T4 at the protein level and described the changing patterns of the proteins' expression in this progression. JAK2, keratin 10, and IL-3Rα were identified as markers for prognosis. The risk model based on histological grade, T classification, N classification, JAK2, and IL-3Rα can predict the prognosis with 85.5% accuracy.

CONCLUSION

This study indicated that dysregulated signaling proteins can be selected as useful biomarkers for tumor classification and predicting the outcome in patients with laryngeal SCC. The changing patterns of the proteins' expression in different stages were related to the more malignant transformation and further studies will focus on the role of these proteins in laryngeal SCC progression.

Headway and hurdles in the clinical development of dietary phytochemicals for cancer therapy and prevention: lessons learned from vitamin A derivatives

Accumulating epidemiologic and preclinical evidence support the pharmacologic use of a variety of dietary chemicals for the prevention and treatment of cancer. However, it will be challenging to translate these findings into routine clinical practice since phytochemicals have pleiotropic biological activities that have to be balanced for optimal efficacy without unacceptable and potentially unanticipated toxicities. Correctly matching patient populations and settings with optimal, natural product-based phytochemical therapies will require a greater understanding of the specific mechanisms underlying the efficacy, toxicity, and resistance of each agent in a variety of normal, premalignant, and malignant settings. This, in turn, necessitates continued commitment from the basic research community to guide carefully designed and informed clinical trials. The most developed class of anticancer phytochemicals consists of the derivatives of vitamin A called retinoids. Unlike other natural product chemicals currently under study, the retinoids have been extensively tested in humans. Over 30 years of clinical investigation has resulted in several disappointments, but there were some spectacular successes where certain retinoid-based protocols are now FDA-approved standard of care therapies to treat specific malignancies. Furthermore, retinoids are one of the most evaluated pharmacologic agents in the ultra-challenging setting of interventional cancer prevention. This review will summarize the development of retinoids in cancer therapy and prevention with an emphasis on currently proposed mechanisms mediating their efficacy, toxicity, and resistance.

Prediction of survival in resected non-small cell lung cancer using a protein expression-based risk model: implications for personalized chemoprevention and therapy

PURPOSE

Patients with resected non-small cell lung cancer (NSCLC) are at risk for recurrence of disease, but we do not have tools to predict which patients are at highest risk. We set out to create a risk model incorporating both clinical data and biomarkers.

EXPERIMENTAL DESIGN

We assembled a comprehensive database with archival tissues and clinical follow-up from patients with NSCLC resected between 2002 and 2005. Twenty-one proteins identified from our preclinical studies as related to lung carcinogenesis were investigated, including pathways related to metabolism, DNA repair, inflammation, and growth factors. Expression of proteins was quantified using immunohistochemistry. Immunohistochemistry was chosen because it is widely available and can be performed on formalin-fixed paraffin-embedded specimens. Cox models were fitted to estimate effects of clinical factors and biomarkers on recurrence-free survival (RFS) and overall survival (OS).

RESULTS

A total of 370 patients are included in our analysis. With median follow-up of 5.3 years, median OS is 6.4 years. A total of 209 cases with recurrence or death were observed. Multicovariate risk models for RFS and OS were developed including relevant biomarkers, age, and stage. Increased expression of phospho-adenosine monophosphate-activated protein kinase (pAMPK), phospho-mTOR (pmTOR), epithelial cell adhesion molecule (EpCAM), and calcium/calmodulin-dependent serine protein kinase were significant (P < 0.05) predictors for favorable RFS; insulin receptor, chemokine (C-X-C motif) receptor 2 (CXCR2), and insulin-like growth factor-1 receptor predicted for unfavorable RFS. Significant (P < 0.05) predictors for favorable OS include pAMPK, pmTOR, and EpCAM; CXCR2 and flap structure-specific endonuclease-1 predicted unfavorable OS.

CONCLUSION

We have developed a comprehensive risk model predictive for recurrence in our large retrospective database, which is one of the largest reported series of resected NSCLC.

Pharmacogenetics of the nuclear hormone receptors: the missing link between environment and drug effects?

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.

Oral premalignancy: the roles of early detection and chemoprevention

Premalignancy and chemoprevention studies in head and neck cancer typically focus on the oral cavity. Avoiding or cessation of alcohol and smoking, early detection of potentially malignant disorders or cancer, and early detection of recurrent and/or second primary tumor form the basis of prevention of oral cancer. Analysis of tissue prospectively collected in evaluation of retinoids for chemoprevention trials allowed identification of molecular biomarkers of risk to develop oral cancer, loss of heterozygosity being the most validated one. Improving risk assessment and identification of new targets for chemoprevention represent the main challenges in this field.

Janus kinase 2 polymorphisms are associated with risk in patients with gastric cancer in a Chinese population

AIM

To evaluate the impact of the Janus kinase 2 single nucleotide polymorphisms (SNPs) on gastric cancer risk.

METHODS

In this hospital-based, case-control study, the genotypes were identified by polymerase chain reaction-restriction fragment length polymorphism protocols in 661 individuals (359 gastric cancer patients and 302 age and sex matched cancer-free controls).

RESULTS

Both the frequency of A allele in rs2230724 and G allele in rs1887427 were more frequent in patients with gastric cancer (P = 0.013 and 0.001, respectively). Compared with the common genotype, subjects with the (AG+AA) genotypes of rs2230724 and the (AG+GG) genotypes of rs1887427 had a 59% and 98% increased risk of developing gastric cancer, respectively (P = 0.010, adjusted OR = 1.59, 95% CI = 1.12-2.27; P<0.001, adjusted OR = 1.98, 95% CI = 1.39-2.81, respectively). Further stratified analysis showed that the association between the risk of gastric cancer and the rare genotypes of rs2230724 were more profound in the subgroups of elder individuals (>56 years), males, nonsmokers and urban subjects, while the association between the risk and the rare genotypes of rs1887427 persisted in subgroups of younger individuals (≤56 years), males, nonsmokers and both of rural and urban subjects.

CONCLUSION

The JAK2 gene rs2230724 and rs1887427 polymorphisms are associated with an increased risk of gastric cancer in a Chinese Han population.

Genetic variants in the PI3K/PTEN/AKT/mTOR pathway predict head and neck cancer patient second primary tumor/recurrence risk and response to retinoid chemoprevention

PURPOSE

The development of second primary tumors (SPT) or recurrence alters prognosis for curatively treated head and neck squamous cell carcinoma (HNSCC) patients. The 13-cis-Retinoic acid (13-cRA) has been tested as a chemoprevention agent in clinical trials with mixed results. Therefore, we investigated whether genetic variants in the PI3K/PTEN/AKT/mTOR pathway could serve as biomarkers to identify which patients are at high risk of an SPT/recurrence, while also predicting response to 13-cRA chemoprevention.

EXPERIMENTAL DESIGN

A total of 137 pathway single-nucleotide polymorphisms were genotyped in 440 patients from the Retinoid Head and Neck Second Primary Trial and assessed for SPT/recurrence risk and response to 13-cRA. Risk models were created based on epidemiology, clinical, and genetic data.

RESULTS

Twenty-two genetic loci were associated with increased SPT/recurrence risk, with six also being associated with a significant benefit following chemoprevention. Combined analysis of these high-risk/high-benefit loci identified a significant (P = 1.54 × 10(-4)) dose-response relationship for SPT/recurrence risk, with patients carrying four to five high-risk genotypes having a 3.76-fold [95% Confidence Interval (CI), 1.87-7.57] increase in risk in the placebo group (n = 215). Patients carrying four to five high-risk loci showed the most benefit from 13-cRA chemoprevention, with a 73% reduction in SPT/recurrence (95% CI, 0.13-0.58) compared with those with the same number of high-risk genotypes who were randomized to receive placebo. Incorporation of these loci into a risk model significantly improved the discriminatory ability over models with epidemiology, clinical, and previously identified genetic variables.

CONCLUSIONS

These results show that loci within this important pathway could identify individuals with a high-risk/high-benefit profile and are a step toward personalized chemoprevention for HNSCC patients.

Lessons learned from randomized clinical trials of micronutrient supplementation for cancer prevention

This review discusses the results of randomized clinical trials of supplemental micronutrients for cancer prevention completed over the past 20 years, including trials of beta-carotene and retinol, vitamins C and E, selenium, folic acid, and vitamin D. Some trials observed significant reductions in risk, whereas others observed significant increases in risk of the primary cancer endpoint. In considering these trials, it appears that supplementation targeted to populations with low status of the nutrient of interest may prevent cancer, whereas supplementation in populations with higher status or to achieve pharmacological exposures may promote cancer. Observational epidemiologic evidence coupled with these trial results supports the concept of a U-shaped curve for micronutrients in relation to cancer prevention. Based on these data, nutrient supplements are not currently recommended for cancer prevention in the general population. The hypothesis that groups with low nutrient status may benefit from supplementation has yet to be formally tested.

The BATTLE to personalize lung cancer prevention through reverse migration

Agents can enter clinical development for cancer prevention either initially or after previous development for a different indication, such as arthritis, with both approaches consuming many years of development before an agent is fully evaluated for cancer prevention. We propose the following, third approach: reverse migration, that is, importing agents, targets, and study designs to personalize interventions and concepts developed in advanced cancer to the setting of cancer prevention. Importing these "ready-made" features from therapy will allow reverse migration to streamline preventive agent development. We recently reported the Biomarker-integrated Approaches of Targeted Therapy for Lung Cancer Elimination (BATTLE) trial of personalized lung cancer therapy and now propose the reverse migration development of personalized lung cancer prevention based on the BATTLE model.

The retinoid X receptors and their ligands

This chapter presents an overview of the current status of studies on the structural and molecular biology of the retinoid X receptor subtypes α, β, and γ (RXRs, NR2B1-3), their nuclear and cytoplasmic functions, post-transcriptional processing, and recently reported ligands. Points of interest are the different changes in the ligand-binding pocket induced by variously shaped agonists, the communication of the ligand-bound pocket with the coactivator binding surface and the heterodimerization interface, and recently identified ligands that are natural products, those that function as environmental toxins or drugs that had been originally designed to interact with other targets, as well as those that were deliberately designed as RXR-selective transcriptional agonists, synergists, or antagonists. Of these synthetic ligands, the general trend in design appears to be away from fully aromatic rigid structures to those containing partial elements of the flexible tetraene side chain of 9-cis-retinoic acid. This article is part of a Special Issue entitled Advances in High Density Lipoprotein Formation and Metabolism: A Tribute to John F. Oram (1945-2010).

A strong case for personalized, targeted cancer prevention

The study reported by Lee and colleagues in this issue of the journal (beginning on page 185) incorporated global genetic variation within a new assessment of the outcome of a previously reported phase-III trial of low-dose 13-cis-retinoic acid (13-cRA) for preventing second primary tumors (SPT) or the recurrence of head-and-neck cancer. This analysis identified genotypes of common single-nucleotide polymorphisms (SNP) and cumulative effect and potential gene-gene interactions that were highly associated with increased placebo-arm risk (prognostic) and/or with reduced treatment-arm risk and longer event-free survival (predictive). For example, the wild-type rs3118570 SNP of the retinoid X receptor alpha gene (carried by 71% of the 13-cRA trial population) marked a 3.33-fold increased SPT/recurrence risk in the placebo arm and a 38% reduced risk in the treatment arm. Adding two other informative genotypes strengthened the treatment-arm risk reduction to 76%, although the genotype trio reflected only 13% of the trial population. This report extends the concept of personalized therapy to cancer prevention.