A functional lncRNA HOTAIR genetic variant contributes to gastric cancer susceptibility

The identification of two regulatory ESCC susceptibility genetic variants in the TERT-CLPTM1L loci

The chromosome 5p15.33 TERT-CLPTM1L region has been identified by genome-wide association studies as a susceptibility locus of multiple malignancies. However, the involvement of this locus in esophageal squamous cell carcinoma (ESCC) development is still largely unclear. We fine-mapped the TERT-CLPTM1L region through genotyping 15 haplotype-tagging single nucleotide polymorphisms (htSNPs) using a two stage case-control strategy. After analyzing 2098 ESCC patients and frequency-matched 2150 unaffected controls, we found that rs2853691, rs2736100 and rs451360 genetic polymorphisms are significantly associated with ESCC risk in Chinese (all P<0.05). Reporter gene assays indicated that the ESCC susceptibility SNP rs2736100 locating in a potential TERT intronic promoter has a genotype-specific effect on TERT expression. Similarly, the CLPTM1L rs451360 SNP also showed allelic impacts on gene expression. After measuring TERT and CLPTM1L expression in sixty-six pairs of esophageal cancer and normal tissues, we observed that the rs2736100 G risk allele carriers showed elevated oncogene TERT expression. Also, subjects with the rs451360 protective T allele had much lower oncogene CLPTM1L expression than those with G allele in tissue specimens. Results of these analyses underline the complexity of genetic regulation of telomere biology and further support the important role of telomerase in carcinogenesis. Our data also support the involvement of CLPTM1L in ESCC susceptibility.

A systematic review and meta-analysis of the association between long non-coding RNA polymorphisms and cancer risk

It has been suggested that long non-coding RNA (lncRNA) gene polymorphisms are associated with cancer risk. In this article, we conducted a systematic review related to studies on the association between lncRNA single-nucleotide polymorphisms (SNPs) and the overall risk of cancer. A total 17 SNPs in four common lncRNA genes were included in the meta-analysis. In the lncRNA H19, the rs2735971 A/G, rs2839698C/T, and rs3024270 G/C polymorphisms, but not rs217727C/T, were correlated with overall cancer risk. The results also suggested that other SNPs were correlated with overall cancer risk, namely, two in HOTAIR (HOX transcript antisense RNA: rs920778C/T and rs7958904 G/C) and two in PRNCR1 (rs1016343C/T and rs16901946 A/G). No association was found between the three ZNRD1-AS1 (ZNRD1 antisense RNA 1) SNPs and the risk of cancer. In summary, our findings suggest that quite a few studied lncRNA SNPs are associated with overall cancer risk; therefore, they are potential predictive biomarkers for the risk of cancer. Moreover, other lncRNA SNPs investigated were also relevant to cancer but studies on them are limited, and they were also briefly reviewed as candidate cancer markers.

Short leukocyte telomere length, alone and in combination with smoking, contributes to increased risk of gastric cancer or esophageal squamous cell carcinoma

In humans, telomeres shorten along with division of somatic cells. Shortened telomere length might result in genomic instability and has been associated with several malignancies. However, the findings in different populations remain conflicting. Therefore, we assessed the association of telomere length in peripheral blood leukocytes with risk of gastric cancer (GC) or esophageal squamous cell carcinoma (ESCC) in a Chinese Han population. A total of 574 GC cases, 740 ESCC cases and 774 age- and sex-matched healthy controls were included in this analysis. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by logistic regression. The GC or ESCC patients had significantly shorter relative telomere length (RTL) (median ± SD: GC: 1.20 ± 0.42; ESCC: 1.27 ± 0.48) than controls (1.41 ± 0.58). Four-fold increased GC risk (OR = 4.10, 95% CI = 2.78-6.05, P = 1.10 × 10^-12) or 1.56-fold increased ESCC risk (95% CI = 1.12-2.18, P = 0.009) among subjects in the shortest quartile of telomere length was found compared with the highest quartile. We also observed a cumulative effect between short RTL and smoking in intensifying risk of GC (P = 4.50 × 10^-9) or ESCC (P = 5.92 × 10^-33). Moreover, there were cumulative effects between RTL, smoking and drinking in elevating risk of GC (P_trend = 0.001) or ESCC (P_trend = 1.57 × 10^-32). Interestingly, RTL-related rs621559 and rs398652 genetic variants are significantly associated with GC risk. These results indicate that short RTL is involved in susceptibility to developing GC or ESCC, alone and in a gene-environment interaction manner. Short telomere length might be a potential molecular marker, in combination with lifestyle risk factors, to identify high-risk individuals.

A Novel Genetic Variant in Long Non-coding RNA Gene NEXN-AS1 is Associated with Risk of Lung Cancer

Lung cancer etiology is multifactorial, and growing evidence has indicated that long non-coding RNAs (lncRNAs) are important players in lung carcinogenesis. We performed a large-scale meta-analysis of 690,564 SNPs in 15,531 autosomal lncRNAs by using datasets from six previously published genome-wide association studies (GWASs) from the Transdisciplinary Research in Cancer of the Lung (TRICL) consortium in populations of European ancestry. Previously unreported significant SNPs (P value < 1 × 10-7) were further validated in two additional independent lung cancer GWAS datasets from Harvard University and deCODE. In the final meta-analysis of all eight GWAS datasets with 17,153 cases and 239,337 controls, a novel risk SNP rs114020893 in the lncRNA NEXN-AS1 region at 1p31.1 remained statistically significant (odds ratio = 1.17; 95% confidence interval = 1.11-1.24; P = 8.31 × 10-9). In further in silico analysis, rs114020893 was predicted to change the secondary structure of the lncRNA. Our finding indicates that SNP rs114020893 of NEXN-AS1 at 1p31.1 may contribute to lung cancer susceptibility.

HOTAIR rs920778 polymorphism is associated with ovarian cancer susceptibility and poor prognosis in a Chinese population

AIM

The aim of this study was to determine if HOTAIR rs920778 polymorphism is associated with ovarian cancer susceptibility and prognosis.

MATERIALS & METHODS

The data were obtained from two independent groups including 329 ovarian cancer patients and 680 cancer-free, age-matched women. Blood samples were collected and genomic DNA was extracted for genotyping.

RESULTS

TT genotype and T allele of HOTAIR rs920778 were significantly associated with a decreased ovarian cancer risk (p = 0.0004 and p < 0.0001, respectively), which associated with advanced tumor stage, lymph node metastasis and poor prognosis. Moreover, TT and TC carriers obtained a much shorter survival (p = 0.026).

CONCLUSION

These findings propose that HOTAIR rs920778 polymorphism influences ovarian cancer susceptibility and prognosis, and further studies are warranted in other populations.

Identification of genetic variation in the lncRNA HOTAIR associated with HPV16-related cervical cancer pathogenesis

PURPOSE

Previously, over-expression of the long noncoding RNA (lncRNA) HOTAIR has been found to be associated with the invasive and metastatic capacities of several epithelial cancers, including cervical cancer (CaCx). Here, we aimed at identifying functionally relevant genetic variants that may be employed to differentiate between clinically distinct CaCx subtypes, i.e., those exhibiting high HOTAIR levels and molecular signatures of metastasis and those lacking such signatures in the presence of low HOTAIR expression levels.

METHODS

Genomic DNA isolated from various cervical tissue samples (characterized by histopathology and HPV status) was used for HOTAIR amplicon sequencing, followed by validation of the findings by Sanger sequencing. The impact of the genetic variants found on the secondary structure of HOTAIR and the concomitant alterations in miRNA binding sites were determined through in silico analysis, followed by miRNA expression analysis by quantitative real-time PCR and confirmation of miRNA binding using a luciferase reporter assay.

RESULTS

We found that rs2366152C was over-represented [OR_age-adjusted = 2.58 (1.23-5.57); p = 0.014] in low HOTAIR expressing HPV positive CaCx cases compared to HPV negative controls. This genetic variant showed the propensity of a secondary structure alteration and gain of a miR-22 binding site in HOTAIR, which was found to be concordant with miR-22 over-expression in low HOTAIR CaCx cases compared to controls. We found that miR-22 expression negatively correlated with HOTAIR and E7 expression in HPV16 positive cases and in an E7 transfected HPV negative CaCx-derived cell line (C33A), but was not altered in high HOTAIR cases compared to controls. Reduced luciferase activity of a HOTAIR rs2366152C expression plasmid in C33A cells through miR-22 co-transfection confirmed the ability of miR-22 to specifically target rs2366152C-harbouring HOTAIR lncRNA in CaCx cells, ultimately leading to its down-regulation.

CONCLUSIONS

Our data indicate that rs2366152C not only has the potential to serve as a marker for singling out CaCx cases lacking metastatic molecular signatures, but also to explain the functional inactivation of HOTAIR in these cases, including the mechanism of its down-regulation.

Onco-lncRNA HOTAIR and its functional genetic variants in papillary thyroid carcinoma

The role of long noncoding RNA (lncRNA) HOX transcript antisense RNA (HOTAIR) and its functional single nucleotide polymorphisms (SNPs) in papillary thyroid carcinoma (PTC) is still largely unclear. Therefore, we investigated the involvement of lncRNA HOTAIR and its three haplotype-tagging SNPs (htSNPs) in PTC. There was higher expression of HOTAIR in PTC tissues compared to normal tissues. A series of gain-loss assays demonstrated that HOTAIR acts as a PTC oncogene via promoting tumorigenic properties of PTC cells. Additionally, the functional HOTAIR rs920778 genetic variant was a PTC susceptibility SNP. Subjects with the HOTAIR rs920778 TT genotype had an odds ratio (OR) of 1.88, 1.25 and 1.61 (P = 6.0 × 10(-6), P = 0.028 and P = 3.2 × 10(-5)) for developing PTC in Shandong, Jiangsu and Jilin case-control sets compared with subjects with the CC genotype. This statistically significant associations were only found between the rs920778 genetic polymorphism and PTC risk in females but not in males. The allele-specific regulation on HOTAIR expression by the rs920778 SNP was confirmed both in vitro and in vivo. Our results demonstrate that functional SNPs influencing lncRNA regulation may explain a part of PTC genetic basis.

The Sp1-mediaded allelic regulation of MMP13 expression by an ESCC susceptibility SNP rs2252070

Metallopeptidase 13 (MMP13), a well-known and highly regulated zinc-dependent MMP collagenase, plays a crucial part in development and progression of esophageal squamous cell carcinoma (ESCC). Therefore, we examined associations between ESCC susceptibility and four haplotype-tagging single nucleotide polymorphisms (htSNPs) using a two stage case-control strategy. Odds ratios (OR) and 95% confidence intervals (95% CI) were computed by logistic regression model. After analyzing 1588 ESCC patients and frequency-matched 1600 unaffected controls, we found that MMP13 rs2252070 G > A genetic polymorphism is significantly associated with ESCC risk in Chinese Han populations (GA: OR = 0.63, 95% CI = 0.54-0.74, P = 1.7 × 10(-6), AA: OR = 0.73, 95% CI = 0.66-0.81, P = 1.8 × 10(-6)). Interestingly, the rs2252070 G-to-A change was shown to diminish a Sp1-binding site in ESCC cells. Reporter gene assays indicated that the rs2252070 A allele locating in a potential MMP13 promoter has low promoter activities. After measuring MMP13 gene expression in sixty-six pairs of esophageal cancer and normal tissues, we observed that the rs2252070 A protective allele carriers showed decreased oncogene MMP13 expression. Results of these analyses underline the support of the notion that MMP13 might function as a key oncogene in esophageal carcinogenesis.

The associations of vascular endothelial growth factor gene polymorphisms with susceptibility to osteosarcoma: evidence from a meta-analysis

Several studies have investigated the associations of the vascular endothelial growth factor (VEGF) gene polymorphisms with the susceptibility to osteosarcoma, while their conclusions are conflicting. This meta-analysis was performed to provide a comprehensive assessment on those associations. Electronic bibliographic databases were searched for potential studies focused on the relationship between VEGF polymorphisms and the susceptibility to osteosarcoma on 10 December 2015. Pooled odds ratios with 95% confidence intervals were conducted to assess the associations. After strict screening process, six articles consisted of 1220 osteosarcoma patients and 1576 controls were selected. The pooled results suggested that VEGF-2578C/A polymorphism was significantly associated with osteosarcoma risk in all genetic models as well as VEGF-634G/C polymorphism. When it came to VEGF+936C/T polymorphism, we detected significant associations under allele contrast, heterozygote, dominant and recessive models. As to VEFG-460T/C polymorphism, significant associations were demonstrated in allele contrast and heterozygote models. With regard to VEGF-1156G/A polymorphism, significant association was observed only in alleles contrast model. However, there was no significant association between VEGF-1612G/A polymorphism and risk of osteosarcoma. This meta-analysis suggests that these polymorphisms comprised of VEGF-2578C/A, VEGF-1156G/A, VEGF+936C/T, VEGF-634G/C and VEGF-460T/C are associated with osteosarcoma risk in Chinese Han population.

Quantitative Assessment of the Polymorphisms in the HOTAIR lncRNA and Cancer Risk: A Meta-Analysis of 8 Case-Control Studies

HOX transcript antisense intergenic RNA (HOTAIR) is a long non-coding RNA (lncRNA) that functions as an oncogenic molecule in different cancer cells. Genetic variants of HOTAIR may affect the activity of certain regulatory factors and further regulate the aberrant expression of HOTAIR, which might be underlying mechanisms that affect tumour susceptibility and prognosis. Recently, several studies have been performed to examine the possible link between polymorphisms in HOTAIR and cancer risk; however, the results have been inconclusive. Therefore, we performed a meta-analysis to estimate the associations between HOTAIR polymorphisms (rs920778, rs4759314 and rs1899663) and cancer risk. Eight studies comprising 7,151 cases and 8,740 controls were included in our study. Overall, no significant associations between the HOTAIR polymorphisms (rs920778, rs4759314 and rs1899663) and cancer risk were observed. However, in further stratified analyses, the variant T allele of rs920778 exhibited a significant increased risk of developing digestive cancers (dominant model: OR = 1.44; 95% CI = 1.31–1.59). These findings provided evidence that HOTAIR rs920778 may modify the susceptibility to certain cancer types. Further studies incorporating subjects with different ethnic backgrounds combined with re-sequencing of the marked region and functional evaluations are warranted.

Genetic variants of lncRNA HOTAIR contribute to the risk of osteosarcoma

Osteosarcoma (OS) is the most common primary malignant bone tumor in adolescents and young adults. However, the essential mechanisms underlying osteosarcomagenesis remain obscure. The HOTAIR, a well-known long noncoding RNA (lncRNA), is involved in pathogenesis and progress of multiple tumors. To reveal the potential role of lncRNA HOTAIR in OS carcinogenesis, we conducted a two-stage, case-control study among Chinese population with 900 OS cases and 900 controls to evaluated associations of its genetic variants with OS risk. We found that C allele of rs7958904 was associated with a significantly decreased OS risk when compared with G allele (OR: 0.77; 95% CI: 0.67-0.90; P = 6.77×10-4). Functional analyses on HOTAIR Expression showed that the expression level of HOTAIR in OS tissues was significantly higher than that in corresponding normal tissues, and subjects with the rs7958904 CC genotype had significantly lower HOTAIR RNA levels than those of other genotypes. This should be the first study to examine the association between HOTAIR variants and OS risk.

Integrated analysis of long non-coding RNA competing interactions reveals the potential role in progression of human gastric cancer

Abnormal expression of long non-coding RNAs (lncRNAs) have been shown to play an important role in tumor biology. The Cancer Genome Atlas (TCGA) platform is a large sample sequencing database of lncRNAs, and further analysis of the associations between these data and patients' clinical related information can provide new approaches to find the functions of lncRNA. In the present study, 361 RNA sequencing profiles of gastric cancer (GC) patients were selected from TCGA. Then, we constructed the lncRNA-miRNA-mRNA competitive endogenous RNA (ceRNA) network of GC. There were 25 GC specific lncRNAs (fold change >2, p<0.05) identified, 19 of them were included in ceRNA network. Subsequently, we selected these 19 key lncRNAs and analyzed the correlations with clinical features and overall survival, 14 of them were discriminatively expressed with tumor size, tumor grade, TNM stage and lymphatic metastasis (p<0.05). In addition, eight lncRNAs (RPLP0P2, FOXD2-AS1, H19, TINCR, SLC26A4-AS1, SMIM10L2A, SMIM10L2B and SNORD116-4) were found to be significantly associated with overall survival (log-rank p<0.05). Finally, two key lncRNAs HOTAIR and UCA1 were selected for validation of their expression levels in 82 newly diagnosed GC patients by qRT-PCR. Results showed that the fold changes between TCGA and qRT-PCR were 100% in agreement. In addition, we also found that HOTAIR was significantly correlated with tumor size and lymphatic metastasis (p<0.05), and UCA1 was significantly correlated with tumor size, TNM stage and lymphatic metastasis (p<0.05). The clinical relevance of the two lncRNAs and the bioinformatics analysis results were almost the same. Overall, our study showed the GC specific lncRNAs expression patterns and a ceRNA network in GC. Clinical features related to GC specific lncRNAs also suggested these lncRNAs are worthwhile for further study as novel candidate biomarkers for the clinical diagnosis of GC and potential indicators for prognosis.

Genetic Polymorphisms in Long Noncoding RNA H19 Are Associated With Susceptibility to Breast Cancer in Chinese Population

H19, a maternally expressed imprinted gene transcribing a long noncoding RNA, has previously been reported to be involved in tumorigenesis and cancer progression. However, the association between the H19 polymorphisms and breast cancer (BC) susceptibility has remained elusive. The aim of this study was to evaluate the associations between 2 H19 haplotype tagging SNPs (rs3741219 T>C, rs217727 C>T) and the risk of breast cancer. Our study comprised 464 BC patients and 467 cancer-free controls in China. rs3741219 and rs217727 were genotyped with polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) and created restriction site PCR (CRS-RFLP) assays, respectively. False-positive report probability (FPRP) was calculated to test the false-positive association. On performing univariate analysis, no significant association between H19 polymorphisms (rs3741219 and rs217727) and BC was observed. However, in further stratified analyses, CT+TT genotypes of rs217727 had a significantly lower risk of breast cancer among women with number of pregnancy >2 (OR = 0.79; 95% CI = 0.55-0.97). CT genotype of rs217727 was associated with ER positivity (OR = 2.19; 95 % CI = 1.07-4.45) and HER-2 positivity (OR = 1.34; 95 % CI = 1.05-2.12). It was proved that our results were less likely to be false positives according to false-positive report probability calculation. Our findings extend available data on the association of H19 polymorphisms and BC susceptibility. Further validation in large population or cohort studies is needed.

Discovery of a novel genetic susceptibility locus on X chromosome for systemic lupus erythematosus

Introduction

Systemic lupus erythematosus (SLE) is an autoimmune connective tissue disease affecting predominantly females. To discover additional genetic risk variants for SLE on the X chromosome, we performed a follow-up study of our previously published genome-wide association study (GWAS) data set in this study.

Methods

Twelve single nucleotide polymorphisms (SNPs) within novel or unpublished loci with P-value < 1.00 × 10⁻⁰² were selected for genotype with a total of 2,442 cases and 2,798 controls(including 1,156 cases and 2,330 controls from central China, 1,012 cases and 335 controls from southern China and 274 cases and 133 controls from northern China) using Sequenom Massarry system. Associaton analyses were performed using logistic regression with sample region as a covariate through PLINK 1.07 software.

Results

Combined analysis in discovery and central validation dataset discovered a novel locus rs5914778 within LINC01420 associated with SLE at genome-wide significance (P = 1.00 × 10⁻⁰⁸; odds ratio (OR) = 1.32). We also confirmed rs5914778 in the southern Chinese sample cohort (P = 5.31 × 10⁻⁰⁵; OR = 1.51), and meta-analysis of the samples from the discovery, central and southern validations regions provided robust evidence for the association of rs5914778 (P = 5.26 × 10⁻¹²; OR = 1.35). However, this SNP did not show association with SLE in the northern sample (P = 0.33). Further analysis represent the association of northern was significantly heterogeneous compared to central and southern respectively.

Conclusions

Our study increases the number of established susceptibility loci for SLE in Han Chinese population and has further demonstrated the important role of X-linked genetic risk variants in the pathogenesis of SLE in Chinese Han population.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0857-1) contains supplementary material, which is available to authorized users.

A functional HOTAIR rs12826786 C>T polymorphism is associated with breast cancer susceptibility and poor clinicopathological characteristics in a Turkish population: a hospital-based case-control study

Hox transcript antisense intergenic RNA (HOTAIR), a long non-coding RNA (lncRNA), is pervasively overexpressed and correlated with tumor invasion, progression, metastasis, and poor prognosis in various human cancers including breast cancer (BC) that plays a role as an oncogenic molecule. A common functional single-nucleotide polymorphism (SNP) (rs12826786 C>T) at the HOTAIR promoter has been reported to influence HOTAIR expression and gastric adenocarcinoma susceptibility, but relation of HOTAIR rs12826786 C>T polymorphism with BC susceptibility and clinicopathological characteristics has yet to be reported. To explore the association of the HOTAIR rs12826786 C>T polymorphism with the risk of BC in a Turkish population, a hospital-based case-control study was carried out consisting of 123 BC patients and 122 age-matched healthy controls. HOTAIR rs12826786 C>T polymorphism was determined by real-time polymerase chain reaction (PCR) using TaqMan assay. We found that women carrying TT genotype of HOTAIR rs12826786 C>T polymorphism had an increased risk of developing BC in both codominant (odds ratio (OR) = 2.24, 95 % confidence interval (CI) 1.05-4.81, P = 0.02) and recessive (OR = 2.49, 95 % CI 1.25-4.97, P = 0.008) inheritance models. Moreover, TT genotype of HOTAIR rs12826786 C>T polymorphism was significantly related with multiple clinicopathological characteristics concerned with worse BC progression such as advanced TNM stage (III and IV), larger tumor size (T3 and T4), and distant metastasis (M1), as well as poor histological grade (III) (P < 0.05). Because of our results put forward for the first time that TT genotype of HOTAIR rs12826786 C>T polymorphism might play crucial roles in genetic susceptibility and poor prognosis for BC in Turkish population, further independent studies are needed to confirm our results in a larger series, as well as in patients of distinct populations.

Dysregulation of non-coding RNAs in gastric cancer

Gastric cancer (GC) is one of the most common cancers in the world and a significant threat to the health of patients, especially those from China and Japan. The prognosis for patients with late stage GC receiving the standard of care treatment, including surgery, chemotherapy and radiotherapy, remains poor. Developing novel treatment strategies, identifying new molecules for targeted therapy, and devising screening techniques to detect this cancer in its early stages are needed for GC patients. The discovery of non-coding RNAs (ncRNAs), primarily microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), helped to elucidate the mechanisms of tumorigenesis, diagnosis and treatment of GC. Recently, significant research has been conducted on non-coding RNAs and how the regulatory dysfunction of these RNAs impacts the tumorigenesis of GC. In this study, we review papers published in the last five years concerning the dysregulation of non-coding RNAs, especially miRNAs and lncRNAs, in GC. We summarize instances of aberrant expression of the ncRNAs in GC and their effect on survival-related events, including cell cycle regulation, AKT signaling, apoptosis and drug resistance. Additionally, we evaluate how ncRNA dysregulation affects the metastatic process, including the epithelial-mesenchymal transition, stem cells, transcription factor activity, and oncogene and tumor suppressor expression. Lastly, we determine how ncRNAs affect angiogenesis in the microenvironment of GC. We further discuss the use of ncRNAs as potential biomarkers for use in clinical screening, early diagnosis and prognosis of GC. At present, no ideal ncRNAs have been identified as targets for the treatment of GC.

Genetic Variations and Gastric Cancer

<b><i>Background:</i></b> Gastric cancer (GC) has an apparent hereditary component. However, in a large fraction of gastric cases, no known genetic syndrome or family history can be identified, suggesting the presence of ‘missing heritability' in GC etiology. Genome-wide association studies (GWAS) and traditional candidate gene studies have both led to the identification of multiple replicable common genetic variants associated with GC risk. <b><i>Summary:</i></b> We summarize the genetic variants associated with GC risk identified up to date. Achievements derived from translational cancer research including the following aspects: (a) contribution to the our understanding of gastric tumorigenesis, (b) guidance to individualized treatment and (c) prediction of patient prognosis. We also prospect future research direction such as post-GWAS analyses and rare variants studies. <b><i>Key Message:</i></b> Many genetic variants were found through GWAS or candidate gene studies, and interpreting their underlying mechanisms will help us translate risk profiles generated from these variations into use in the clinical setting for targeted screening and treatment. <b><i>Practical Implications:</i></b> Investigation of the potential use of genetic variations as prognostic and predictive markers is a developing field. Many people could benefit from a better understanding of genetic polymorphisms to potentially identify a priori individuals who might have the best chance of survival and therefore derive most clinical benefit from treatment. Outcomes of particular scientific interest for molecular epidemiologic studies should include overall survival, recurrence- and progression-free survival, response to treatment, and early and late toxicities stemming from chemotherapy and radiation.