Cheng, Iona C.

Abstract Introduction: Radiotherapy has long been examined in association with second malignancies, but the impact of radiotherapy for initial primary lung cancer (IPLC) on the risk of second primary lung cancer (SPLC) remains controversial. We evaluated associations between IPLC radiotherapy and the risks of SPLC and overall mortality among lung cancer survivors. Methods: We identified 689,785 patients diagnosed with IPLC in 1988-2013 from SEER. We applied cause-specific Cox (CSC) regression to evaluate association between IPLC radiotherapy and SPLC risk, adjusting for age at IPLC diagnosis, IPLC stage and histology, and prior history of cancer. To allow a latency period of exposure to IPLC radiotherapy on SPLC risk, we performed subgroup analyses restricted to patients who survived ≥5 and ≥10 years after IPLC diagnosis. Using Cox regression, we evaluated association between IPLC radiotherapy and overall mortality, adjusting for the same covariates used in the CSC analysis. Mediation analysis quantified the indirect effect of IPLC radiotherapy on overall mortality mediated through radiotherapy-driven SPLC diagnosis. Validation utilized data from 7,758 IPLC patients (496 SPLCs) at Mayo Clinic. Results: Of 689,785 IPLC patients, 18,818 (2.7%) developed SPLC in SEER. IPLC patients treated with radiotherapy had a reduced SPLC risk versus non-irradiated patients when evaluated at the time of initial diagnosis (cause-specific hazard ratio [csHR]=0.90, P<1x10-6). However, the association between IPLC radiotherapy and SPLC risk was reversed when analyses were restricted to those who survived at least 5 years (csHR=1.08, P=0.01) and 10 years (csHR=1.16, P=0.009), thus long-term survivors treated with IPLC radiotherapy having a significantly increased risk of SPLC. Mayo Clinic data showed consistent results, with the effect of IPLC radiotherapy increasing from csHR of 2.41 (P<1x10-6) to 3.38 (P=0.001) among 5-year and 10-year survivors, respectively. Similarly, compared to non-irradiated patients, those treated with IPLC radiotherapy showed a significantly increased risk of overall mortality among 10-year survivors (hazard ratio [HR]=1.46, P<1x10-6 in SEER and HR=1.54, P=5.1X10-5 in Mayo Clinic). Mediation analysis showed that a substantial proportion of the total effect of IPLC radiotherapy on overall mortality—ranging from 32% to 59%—was due to radiotherapy-driven SPLC among 10-year survivors in SEER and Mayo Clinic. Conclusions: IPLC radiotherapy is associated with increased risks of SPLC and overall mortality, with its effects more pronounced among long-term survivors. Citation Format: Eunji Choi, Vicky T. Lam, Jacqueline A. Aredo, Ashok V. Kumar, Jason Wampfler, Julie T. Wu, David C. Christiani, Iona Cheng, Christopher I. Amos, Rayjean J. Hung, Leah M. Backhus, Joel W. Neal, Heather A. Wakelee, Ping Yang, Summer S. Han. Long term effect of radiotherapy on risk of second primary lung cancer and overall mortality among lung cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3445.

Background Initiating screening at an earlier age based on cancer family history is one of the primary recommended strategies for the prevention and detection of early‐onset colorectal cancer (EOCRC), but data supporting the effectiveness of this approach are limited. The authors assessed the performance of family history–based guidelines for identifying individuals with EOCRC. Methods The authors conducted a population‐based, case‐control study of individuals aged 40 to 49 years with (2473 individuals) and without (772 individuals) incident CRC in the Colon Cancer Family Registry from 1998 through 2007. They estimated the sensitivity and specificity of family history–based criteria jointly recommended by the American Cancer Society, the US Multi‐Society Task Force on CRC, and the American College of Radiology in 2008 for early screening, and the age at which each participant could have been recommended screening initiation if these criteria had been applied. Results Family history–based early screening criteria were met by approximately 25% of cases (614 of 2473 cases) and 10% of controls (74 of 772 controls), with a sensitivity of 25% and a specificity of 90% for identifying EOCRC cases aged 40 to 49 years. Among 614 individuals meeting early screening criteria, 98.4% could have been recommended screening initiation at an age younger than the observed age of diagnosis. Conclusions Of CRC cases aged 40 to 49 years, 1 in 4 met family history–based early screening criteria, and nearly all cases who met these criteria could have had CRC diagnosed earlier (or possibly even prevented) if earlier screening had been implemented as per family history–based guidelines. Additional strategies are needed to improve the detection and prevention of EOCRC for individuals not meeting family history criteria for early screening.

Abstract Background Previous genome-wide association studies (GWAS) have identified 42 loci (P < 5 × 10−8) associated with risk of colorectal cancer (CRC). Expanded consortium efforts facilitating the discovery of additional susceptibility loci may capture unexplained familial risk. Methods We conducted a GWAS in European descent CRC cases and control subjects using a discovery–replication design, followed by examination of novel findings in a multiethnic sample (cumulative n = 163 315). In the discovery stage (36 948 case subjects/30 864 control subjects), we identified genetic variants with a minor allele frequency of 1% or greater associated with risk of CRC using logistic regression followed by a fixed-effects inverse variance weighted meta-analysis. All novel independent variants reaching genome-wide statistical significance (two-sided P < 5 × 10−8) were tested for replication in separate European ancestry samples (12 952 case subjects/48 383 control subjects). Next, we examined the generalizability of discovered variants in East Asians, African Americans, and Hispanics (12 085 case subjects/22 083 control subjects). Finally, we examined the contributions of novel risk variants to familial relative risk and examined the prediction capabilities of a polygenic risk score. All statistical tests were two-sided. Results The discovery GWAS identified 11 variants associated with CRC at P < 5 × 10−8, of which nine (at 4q22.2/5p15.33/5p13.1/6p21.31/6p12.1/10q11.23/12q24.21/16q24.1/20q13.13) independently replicated at a P value of less than .05. Multiethnic follow-up supported the generalizability of discovery findings. These results demonstrated a 14.7% increase in familial relative risk explained by common risk alleles from 10.3% (95% confidence interval [CI] = 7.9% to 13.7%; known variants) to 11.9% (95% CI = 9.2% to 15.5%; known and novel variants). A polygenic risk score identified 4.3% of the population at an odds ratio for developing CRC of at least 2.0. Conclusions This study provides insight into the architecture of common genetic variation contributing to CRC etiology and improves risk prediction for individualized screening.

Telomeres cap chromosome ends, protecting them from degradation, double‐strand breaks, and end‐to‐end fusions. Telomeres are maintained by telomerase, a reverse transcriptase encoded by TERT, and an RNA template encoded by TERC. Loci in the TERT and adjoining CLPTM1L region are associated with risk of multiple cancers. We therefore investigated associations between variants in 22 telomere structure and maintenance gene regions and colorectal, breast, prostate, ovarian, and lung cancer risk. We performed subset‐based meta‐analyses of 204,993 directly‐measured and imputed SNPs among 61,851 cancer cases and 74,457 controls of European descent. Independent associations for SNP minor alleles were identified using sequential conditional analysis (with gene‐level p value cutoffs ≤3.08 × 10−5). Of the thirteen independent SNPs observed to be associated with cancer risk, novel findings were observed for seven loci. Across the DCLRE1B region, rs974494 and rs12144215 were inversely associated with prostate and lung cancers, and colorectal, breast, and prostate cancers, respectively. Across the TERC region, rs75316749 was positively associated with colorectal, breast, ovarian, and lung cancers. Across the DCLRE1B region, rs974404 and rs12144215 were inversely associated with prostate and lung cancers, and colorectal, breast, and prostate cancers, respectively. Near POT1, rs116895242 was inversely associated with colorectal, ovarian, and lung cancers, and RTEL1 rs34978822 was inversely associated with prostate and lung cancers. The complex association patterns in telomere‐related genes across cancer types may provide insight into mechanisms through which telomere dysfunction in different tissues influences cancer risk.

Abstract Telomeres are complex structures that cap chromosome ends, protecting them from degradation, double strand breaks and end-to-end fusions. Telomeres are maintained by the enzyme telomerase, which is made up of a reverse transcriptase encoded by TERT, and an RNA template encoded by TERC. The telomere structure itself is composed of proteins encoded by ACD, ACYP2, BICD1, DKC1, DCLRE1B, MPHOSPH6, NAF1, NOLA1, NOLA2, NOLA3, OBFC1, PIK3C3, POT1, RTEL1, TEP1, TERF1, TERF2, TERF21P, TINF2, TNKS/PINX1, TPP1 and ZNF208. Several single nucleotide polymorphisms (SNPs) in the TERT and adjoining CLPTM1L gene region are associated with multiple cancer types, and some are associated with both increased and decreased risks across different cancer types. We systematically characterized the patterns of association between variants in these 25 telomere structure and maintenance genes and risk across five cancer types in the Genetic Association and Mechanisms in Oncology (GAME-ON) consortium. We performed a subset-based meta-analysis (ASSET) of 209,367 directly measured and imputed SNPs, one megabase up- and downstream of these genes, across genome-wide association studies of colorectal (5,100 cases, 4,831 controls), lung (12,160 cases, 16,838 controls), breast (15,748 cases, 18,084 controls), ovarian (4,369 cases, 9,123 controls) and prostate (14,160 cases, 12,724 controls) cancers. Correlations (r2) between SNPs were examined in Haploview using the 1000 Genomes Project CEU population. A total of 87 TERT, 123 TERC and 26 DCLRE1B SNPs were associated with cancer risk at gene-level Bonferroni-corrected p-values of 4.2-7.8×10−6. Patterns of association were similar for prostate and colorectal cancers in DCLRE1B. Much stronger associations were observed in TERT and TERC, with 63 and 24 SNPs reaching genome-wide significance (p&lt;5.0×10−8), respectively. Of these, 9 TERT and 9 TERC SNPs were correlated at r2&lt;0.75. The most strongly associated SNPs in TERT (rs37004, p = 2.6×10−11) and TERC (rs76925190, p = 1.5×10−15) are in regions containing documented risk loci for lung and prostate cancers, respectively. TERT rs37004 (p = 1.2×10−13) and 6 of the other 9 SNPs in TERT were associated only with lung cancer risk. For the other 2 SNPs, there was a suggestion that patterns of risk were opposite for lung and prostate cancers. While TERC rs76925190 was strongly associated with prostate cancer risk (p = 5.4 x10−17), it was also suggestively associated with colorectal cancer risk (p&lt;0.005). This pattern was similar for another 2 of the 9 SNPs, while for the rest, associations were limited to prostate cancer. The complex patterns of association in telomere structure and maintenance genes observed across cancer types may provide insight about the mechanisms through which telomere dysfunction in different tissues influences cancer risk. Citation Format: Sara Karami, Younghun Han, Fredrick R. Schumacher, Zsofia Kote-Jarai, Sara Lindstrom, John S. Witte, Iona Cheng, Shenying Fang, Jiali Han, Peter Kraft, Fengju Song, Rayjean J. Hung, James McKay, Stephen J. Chanock, Mala Pande, Angela Risch, Hongbing Shen, Christopher A. Haiman, Lisa Boardman, Cornelia M. Ulrich, Graham Casey, Ulrike Peters, Nilanjan Chatterjee, Brandon Pierce, Wei Zheng, Christopher I. Amos, Jennifer A. Doherty. Risk loci in telomere structure and maintenance genes across five cancer types: GAME-ON Consortium. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4609. doi:10.1158/1538-7445.AM2015-4609

AbstractBackground: It is widely accepted that chronic inflammation plays a role in the etiology of colorectal cancer. Using a two-stage design, we examined the associations between colorectal cancer and common variation in 37 key genes in the inflammation and innate immunity pathways.Methods: In the discovery stage, 2,322 discordant sibships (2,535 cases, 3,915 sibling controls) from the Colorectal Cancer Family Registry were genotyped for more than 600 tagSNPs and 99 single-nucleotide polymorphisms (SNP) were selected for further examination based on strength of association. In the second stage, 351 SNPs tagging gene regions covered by the 99 SNPs were tested in 4,783 Multiethnic Cohort subjects (2,153 cases, 2,630 controls).Results: The association between rs9858822 in the PPARG gene and colorectal cancer was statistically significant at the end of the second stage (OR per allele = 1.36, Bonferroni-adjusted P = 0.045), based on the “effective” number of markers in stage II (n = 306). The risk allele C was common (frequency 0.3) in African Americans but rare (frequency &lt; 0.03) in whites, Japanese Americans, Latinos, and Native Hawaiians. No statistically significant heterogeneity of effects across race/ethnicity, body mass index (BMI) levels, regular aspirin use, or pack-years of smoking was detected for this SNP. Suggestive associations were also observed for several SNPs in close vicinity to rs9858822.Conclusions: Our results provide new evidence of association between PPARG variants and colorectal cancer risk.Impact: Further replication in independent samples is warranted. Cancer Epidemiol Biomarkers Prev; 22(11); 2094–101. ©2013 AACR.

Objective Genome-wide association studies have identified a large number of single nucleotide polymorphisms (SNPs) associated with a wide array of cancer sites. Several of these variants demonstrate associations with multiple cancers, suggesting pleiotropic effects and shared biological mechanisms across some cancers. We hypothesised that SNPs previously associated with other cancers may additionally be associated with colorectal cancer. In a large-scale study, we examined 171 SNPs previously associated with 18 different cancers for their associations with colorectal cancer. Design We examined 13 338 colorectal cancer cases and 40 967 controls from three consortia: Population Architecture using Genomics and Epidemiology (PAGE), Genetic Epidemiology of Colorectal Cancer (GECCO), and the Colon Cancer Family Registry (CCFR). Study-specific logistic regression results, adjusted for age, sex, principal components of genetic ancestry, and/or study specific factors (as relevant) were combined using fixed-effect meta-analyses to evaluate the association between each SNP and colorectal cancer risk. A Bonferroni-corrected p value of 2.92×10 −4 was used to determine statistical significance of the associations. Results Two correlated SNPs—rs10090154 and rs4242382—in Region 1 of chromosome 8q24, a prostate cancer susceptibility region, demonstrated statistically significant associations with colorectal cancer risk. The most significant association was observed with rs4242382 (meta-analysis OR=1.12; 95% CI 1.07 to 1.18; p=1.74×10 −5 ), which also demonstrated similar associations across racial/ethnic populations and anatomical sub-sites. Conclusions This is the first study to clearly demonstrate Region 1 of chromosome 8q24 as a susceptibility locus for colorectal cancer; thus, adding colorectal cancer to the list of cancer sites linked to this particular multicancer risk region at 8q24.

Abstract Alterations in the expression of microRNAs (miRNAs) contribute to the development and progression of colon cancer, which arises from the accumulation of genetic and epigenetic alterations in the colon tissue. With the advent of next-generation sequencing (NGS), new depths can be reached, allowing for comprehensive profiling of known and novel miRNAs. To profile the miRNAs and their associated target genes in colon cancer, we examined differential expression of miRNAs and predicted target genes between tumor and normal tissue of microsatellite stable (MSS) and CpG island methylator phenotype (CIMP)-negative colon cancer. Ten fresh-frozen colon tumors and 10 adjacent normal mucosa were profiled for miRNAs using the SOLiD NGS platform and mRNA expression analysis was conducted using Affymetrix arrays. To identify differentially expressed miRNAs in tumor versus normal tissue, analysis of variance was conducted that included Bonferroni correction. Integrated expression analysis of miRNAs and their target mRNAs was conducted using Pearson's correlation and the Benjamini and Hochberg's false discovery rate. Both analyses were done using Partek Genomics Suite software. Nineteen miRNAs were significantly differentially expressed in tumor versus normal tissue (fold change ≥ ±2 and p&lt;0.05). Six of these 19 miRNAs have previously been associated with colon cancer (miR-30a, miR-31, miR-135b, miR-182, miR-183 and miR-202). Integrated analysis of miRNA and predicted target mRNA expression yielded 97 significantly correlated miRNA::mRNA pairs for 14 miRNAs with 92 genes (absolute r = 0.71–0.88, q&lt;0.05). Within these miRNA::mRNA pairs, expression levels of the 6 colon cancer-associated miRNAs were correlated with 33 target genes and 8 miRNAs newly identified to be differentially expressed in colon cancer were correlated with 57 target genes. The top functional Ingenuity Pathway Analysis gene ontology categories (p&lt;0.05) for the 92 genes were gastrointestinal disease (18 genes), genetic disorder (21genes), inflammatory disease (15 genes) and cancer (21 genes). The correlated target genes included several genes implicated in colon cancer such as CDH3, NKD1, RGS2, TCFL5 and ZEB2. In summary, deep miRNA sequencing among MSS/CIMP-negative colon tumors confirmed differential expression of 6 colon cancer-associated miRNAs and identified 13 miRNAs not previously reported in colon cancer. Differential expression of most of the discovered miRNAs was correlated with the expression of genes potentially relevant for colon cancer. If confirmed, these miRNAs may serve as new biomarkers for colon cancer and may further our understanding of the epigenetic changes and pathways involved in the development of colon cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-348. doi:10.1158/1538-7445.AM2011-LB-348