Background The rarity of mutations in PALB2, CHEK2 and ATM make it difficult to estimate precisely associated cancer risks. Population-based family studies have provided evidence that at least some of these mutations are associated with breast cancer risk as high as those associated with rare BRCA2 mutations. We aimed to estimate the relative risks associated with specific rare variants in PALB2, CHEK2 and ATM via a multicentre case-control study. Methods We genotyped 10 rare mutations using the custom iCOGS array: PALB2 c.1592delT, c.2816T>G and c.3113G>A, CHEK2 c.349A>G, c.538C>T, c.715G>A, c.1036C>T, c.1312G>T, and c.1343T>G and ATM c.7271T>G. We assessed associations with breast cancer risk (42 671 cases and 42 164 controls), as well as prostate (22 301 cases and 22 320 controls) and ovarian (14 542 cases and 23 491 controls) cancer risk, for each variant. Results For European women, strong evidence of association with breast cancer risk was observed for PALB2 c.1592delT OR 3.44 (95% CI 1.39 to 8.52, p=7.1×10−5), PALB2 c.3113G>A OR 4.21 (95% CI 1.84 to 9.60, p=6.9×10−8) and ATM c.7271T>G OR 11.0 (95% CI 1.42 to 85.7, p=0.0012). We also found evidence of association with breast cancer risk for three variants in CHEK2, c.349A>G OR 2.26 (95% CI 1.29 to 3.95), c.1036C>T OR 5.06 (95% CI 1.09 to 23.5) and c.538C>T OR 1.33 (95% CI 1.05 to 1.67) (p≤0.017). Evidence for prostate cancer risk was observed for CHEK2 c.1343T>G OR 3.03 (95% CI 1.53 to 6.03, p=0.0006) for African men and CHEK2 c.1312G>T OR 2.21 (95% CI 1.06 to 4.63, p=0.030) for European men. No evidence of association with ovarian cancer was found for any of these variants. Conclusions This report adds to accumulating evidence that at least some variants in these genes are associated with an increased risk of breast cancer that is clinically important.
Abstract LB-364: Natural history of age-related lobular involution and impact on breast cancer risk
Cancer Research | July 26, 2016 | Volume: 76 | Issue: 14_Supplement | Pages: LB-364-LB-364
Abstract Background: Age-related lobular involution (LI) is a physiological process in which the terminal duct lobular units of the breast regress as a woman ages. Analyses of breast biopsies from women with benign breast disease (BBD) have found that extent of LI is negatively associated with subsequent breast cancer development. Here we assess the natural course of LI within individual women, and the impact of progressive LI on breast cancer risk. Methods: The Mayo Clinic BBD cohort consists of 13,455 women with BBD from 1967-2001. The BBD cohort includes 1115 women who had multiple benign biopsies, 106 of whom had developed breast cancer. Within this multiple biopsy cohort, the progression of the LI process was examined by age at initial biopsy and time between biopsies. The relationship between LI progression and breast cancer risk was assessed using standardized incidence ratios (SIRs) and by Cox proportional hazards analysis. Results: Women who had multiple biopsies were younger age and had a slightly higher family history of breast cancer as compared with the overall BBD cohort. Extent of LI at subsequent biopsy was greater with increasing time between biopsies and for women age 55+ at initial biopsy. Among women with multiple biopsies, there was a significant association of higher breast cancer risk among those with involution stasis (lack of progression, HR 1.63) as compared with those with involution progression, p = 0.036. Conclusions: The multiple biopsy BBD cohort allows for a longitudinal study of the natural progression of LI. The majority of women in the multiple biopsy cohort showed progression of LI status between benign biopsies, and extent of progression was highest for women who were in the perimenopausal age range at initial biopsy. Progression of LI status between initial and subsequent biopsy was associated with decreased breast cancer risk. Citation Format: Derek Radisky, Daniel W. Visscher, Ryan Frank, Robert A. Vierkant, Stacey J. Winham, Melody L. Stallings-Mann, Tanya L. Hoskin, Aziza Nassar, Celine M. Vachon, Lori A. Denison, Lynn C. Hartmann, Marlene H. Frost, Amy C. Degnim. Natural history of age-related lobular involution and impact on breast cancer risk. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-364.
Abstract 2636: Tumor-infiltrating cytotoxic T-cells are associated with improved survival of colorectal cancer patients
Cancer Research | July 26, 2016 | Volume: 76 | Issue: 14_Supplement | Pages: 2636-2636
Abstract Background: The immune response has been shown to impact the course of colorectal cancer (CRC). Our goal was to examine the survival of CRC patients in relation to tumor-infiltrating cytotoxic (CD8+) T lymphocytes (CTL). We quantified CTLs in tumor epithelial and stromal tissues and correlated them with clinicopathological characteristics and survival of CRC patients in the Iowa Women's Health Study. Methods: Paraffin-embedded tissue samples were available from 465 post-menopausal women diagnosed with incident CRC in 1986-2002. Tumor microarrays were constructed and immunostained with a CD8 antibody (Clone 144B; Dako). CTLs in tumor epithelial and stromal tissues were categorized by an experienced pathologist into non-detected; mild (1-10 cells per core); moderate (11-29 cells); and strong infiltration (≥30 cells per core), and averaged over cores per each person. We used Cox regression to estimate the hazard ratio (HR) and 95% CI for total and CRC death in relation to each CTL score after adjusting for age of diagnosis, SEER stage, grade, body mass, smoking history and integrated molecular pathway for CRC. The tumors were categorized by integrated pathway (traditional, alternate, serrated, unassigned) based on the combination of phenotypes: microsatellite instability (MSI) status, CpG island methylator (CIMP) phenotype; and mutations in BRAF and/or KRAS genes (described in Samadder, 2013). Results: During follow-up until 2011, 31% of participants died from CRC, 36% from all other causes, and 33% were alive (median follow-up: 8.4 y). The Spearman correlation coefficient between epithelial and stromal CTL scores was 0.52. Both scores were inversely correlated with stage at diagnosis and were higher in tumors characterized by MSI-high, CIMP-high and BRAF mutation-positive status. The highest categories in the epithelial and stromal scores were associated with statistically significant decreases in total death (by 44% and 40%, respectively) and CRC death (by 68% and 56%, respectively) compared to lowest categories. After summing epithelial and stromal CTL scores, the combined HRs (95% CI) in the highest versus lowest category were 0.55 (0.38-0.78) for total death (p-trend = 0.0002) and 0.36 (0.20-0.63) for CRC death (p-trend<0.0001). Additional adjustment for surgery, chemotherapy, radiation, and comorbidities did not markedly change the associations. Finally, there was a statistically significant quantitative interaction between stromal score and MSI status in relation to total and CRC death (P for interaction were 0.02 and 0.0001, respectively); HRs were lower for MSI-high than for MS-stable tumors. There was also a significant interaction between smoking status (current versus never) and epithelial CTL score: the HRs for total and CRC death were lowest among never smokers with the highest score. Conclusions. Our study further supports infiltration of tumors with CTLs as an important prognostic factor in CRC. Citation Format: Anna E. Prizment, Robert A. Vierkant, Thomas C. Smyrk, Lori S. Tillmans, Heather H. Nelson, Charles F. Lynch, Stephen N. Thibodeau, Timothy R. Church, James R. Cerhan, Kristin E. Anderson, Paul J. Limburg. Tumor-infiltrating cytotoxic T-cells are associated with improved survival of colorectal cancer patients. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2636.
Assessment of variation in immunosuppressive pathway genes reveals TGFBR2 to be associated with risk of clear cell ovarian cancer