Cancer risks associated with germline PALB2 pathogenic variants - an international study of 524 families

PURPOSE To estimate age-specific relative and absolute cancer risks for breast cancer, and to estimate risks of ovarian, pancreatic, male breast, prostate, and colorectal cancers associated with germline PALB2 pathogenic variants (PVs) as these risks have not been extensively characterized. METHODS We analysed data from 524 families with PALB2 PVs from 21 countries. Complex segregation analysis was used to estimate relative risks (RRs, relative to country-specific population incidences) and absolute risks of cancers. The models allowed for residual familial aggregation of breast and ovarian cancer and were adjusted for the family-specific ascertainment schemes. RESULTS We found associations between PALB2 PVs and risk of female breast cancer (RR=7.18; 95% CI: 5.82-8.85, p=6.5×10-76), ovarian cancer (RR=2.91; 95% CI: 1.40-6.04, p=4.1×10-3), pancreatic cancer (RR=2.37; 95% CI: 1.24-4.50; p=8.7×10-3), and male breast cancer (RR=7.34, 95% CI: 1.28-42.18, p=2.6×10-2). There no evidence for increased risks of prostate or colorectal cancer. The breast cancer RRs declined with age (p-trend=2.0×10-3). After adjusting for family-ascertainment, breast cancer risk estimates based on multiple case families were similar to the estimates from families ascertained through population-based studies (p-difference=0.41). Based on the combined data, the estimated risks to age 80 years were 53% (95% CI: 44-63%) for female breast cancer, 5% (95% CI: 2-10%) for ovarian cancer, 2-3% (95% CI: females: 1-4%; males: 2-5%) for pancreatic cancer, and 1% (95% CI: 0.2-5%) for male breast cancer. CONCLUSION These results confirm PALB2 as a key breast cancer susceptibility gene and establish substantial associations between germline PALB2 PVs and ovarian, pancreatic, and male breast cancers. These findings will facilitate incorporation of PALB2 into risk prediction models and optimise the clinical cancer risk management of PALB2 PV carriers.ERC, CRUK, NIH, NIH

Caveat Emptor: The Perils of Panel Testing in Hereditary Breast Cancer.

In a recent issue of Journal of Clinical Oncology, Beitsch et al1 argue for expanded panel testing in all patients with a diagnosis of breast cancer. Their argument rests on the finding that of patients who met National Comprehensive Cancer Network guidelines, 9.39% had a pathogenic/likely pathogenic (P/LP) variant, whereas of those patients who did not meet National Comprehensive Cancer Network guidelines, 7.9% had a P/LP variant. These figures, however, include many variants in genes that have no definite proven association with an increased risk of breast cancer.2 These results may thus represent incidental findings that could equally be found in an unselected population and will not inform the management of their disease. Indeed, even at below the expected carrier frequency of one in 50, monoallelic variants in the recessively inherited gene MUTYH account for a full 20% of the reported findings in patients who did not meet NCCN guidelines. These findings are not pertinent and amount to population screening

Cancer incidence in relatives of British Fanconi Anaemia patients.

BACKGROUND: Fanconi anemia (FA) is an autosomal recessive DNA repair disorder with affected individuals having a high risk of developing acute myeloid leukaemia and certain solid tumours. Thirteen complementation groups have been identified and the genes for all of these are known (FANCA, B, C, D1/BRCA2, D2, E, F, G, I, J/BRIP1, L, M and N/PALB2). Previous studies of cancer incidence in relatives of Fanconi anemia cases have produced conflicting results. A study of British FA families was therefore carried out to investigate this question, since increases in cancer risk in FA heterozygotes would have implications for counselling FA family members, and possibly also for the implementation of preventative screening measures in FA heterozygotes. METHODS: Thirty-six families took part and data was collected on 575 individuals (276 males, 299 females), representing 18,136 person years. In this cohort, 25 males and 30 females were reported with cancer under the age of 85 years, and 36 cancers (65%) could be confirmed from death certificates, cancer registries or clinical records. RESULTS: A total of 55 cancers were reported in the FA families compared to an estimated incidence of 56.95 in a comparable general population cohort, and the relative risk of cancer was 0.97 (95% C.I. = 0.71-1.23, p = 0.62) for FA family members. Analysis of relative risk for individual cancer types in each carrier probability group did not reveal any significant differences with the possible exception of prostate cancer (RR = 3.089 (95% C.I. = 1.09 - 8.78; Chi2 = 4.767, p = 0.029). CONCLUSION: This study has not shown a significant difference in overall cancer risk in FA families.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

When to Consider Risk-Reducing Mastectomy in BRCA1/BRCA2 Mutation Carriers with Advanced Stage Ovarian Cancer: a Case Study Illustrating the Genetic Counseling Challenges

Germline mutations in BRCA1/BRCA2 significantly increase the risk of breast and ovarian cancer in women. This case report describes a BRCA1 germline mutation identified in a woman with stage IV epithelial ovarian cancer and the provision of genetic counseling about BRCA1-associated breast cancer risk in the three years following diagnosis. The report centers on the patient’s enquiry about risk-reducing breast surgery. We focus on the challenges for health professionals and patients in understanding and balancing the risks and benefits of major prophylactic surgery in the context of a potentially life-limiting cancer diagnosis. Breast cancer risk management in BRCA1/BRCA2 carriers with advanced ovarian cancer is an under-explored area of genetic counseling research. This article includes a case report, a review of the relevant literature and considers some implications for practice.Author Marc Tischkowitz is funded by the European Union Seventh Framework Program (2007–2013)/European Research Council (310018)

Clinical implications of germline mutations in breast cancer genes: RECQL.

BACKGROUND: The identification of new hereditary breast cancer genes is an area of highly active research. In 2015, two independent studies provided initial evidence for a novel breast cancer susceptibility gene, RECQL, a DNA helicase which plays an important role in the DNA damage response. Several subsequent studies in independent patient cohorts have provided further data on RECQL variant frequency in additional populations, some of which have brought in to question the increased breast cancer risk associated with RECQL mutations. RESULTS: The initial reports present findings from whole exome sequencing of high-risk familial breast cancer cases in the French-Canadian, Polish and Han Chinese populations and estimate the carrier frequency of pathogenic RECQL mutations in high-risk breast cancer patients who have previously tested negative for BRCA1 and BRCA2 mutations to be approximately 1-2%. Proposed founder mutations were identified in French-Canadian and Polish populations. Functional studies support loss of function of the helicase activity of RECQL for some of the reported pathogenic mutations. An additional study in a cohort of Southern Chinese high-risk breast cancer patients estimated the frequency of pathogenic RECQL mutations to be 0.54%. A possible Chinese founder mutation was identified, but only a small number of controls were sequenced. Subsequent case-control studies screening for the Polish founder mutation in patients from Germany and Belarus did not find any evidence for increased breast cancer risk for this variant. An Australian case-control study also failed to identify an increased risk of breast cancer associated with RECQL loss of function variants. CONCLUSIONS: RECQL plays an important role in DNA repair, and is a plausible candidate breast cancer susceptibility gene. Initial studies showed evidence of an association between variants in this gene and an increased breast cancer risk in three separate populations, and identified founder mutations with significantly increased odds ratios. However, several subsequent studies have failed to support the association. With the limited and conflicting evidence available, there remains debate as to whether there is an increased breast cancer risk in individuals carrying RECQL loss of function variants. Further studies are required to better quantify the risks associated with RECQL variants and the current evidence base is not sufficient to justify routine inclusion of RECQL on breast cancer gene panels in clinical use. Management of patients in whom RECQL variants have been identified should be based on clinician assessment, in the context of the family history. Further studies are required to better quantify the risks to RECQL mutation carriers and may also guide management and potential therapeutic targeting for patients

Cancer Risks Associated With Germline PALB2 Pathogenic Variants : An International Study of 524 Families

PURPOSE To estimate age-specific relative and absolute cancer risks of breast cancer and to estimate risks of ovarian, pancreatic, male breast, prostate, and colorectal cancers associated with germline PALB2 pathogenic variants (PVs) because these risks have not been extensively characterized. METHODS We analyzed data from 524 families with PALB2 PVs from 21 countries. Complex segregation analysis was used to estimate relative risks (RRs; relative to country-specific population incidences) and absolute risks of cancers. The models allowed for residual familial aggregation of breast and ovarian cancer and were adjusted for the family-specific ascertainment schemes. RESULTS We found associations between PALB2 PVs and risk of female breast cancer (RR, 7.18; 95% CI, 5.82 to 8.85; P = 6.5 x 10(-76)), ovarian cancer (RR, 2.91; 95% CI, 1.40 to 6.04; P = 4.1 x 10(-3)), pancreatic cancer (RR, 2.37; 95% CI, 1.24 to 4.50; P = 8.7 x 10(-3)), and male breast cancer (RR, 7.34; 95% CI, 1.28 to 42.18; P = 2.6 x 10(-2)). There was no evidence for increased risks of prostate or colorectal cancer. The breast cancer RRs declined with age (P for trend = 2.0 x 10(-3)). After adjusting for family ascertainment, breast cancer risk estimates on the basis of multiple case families were similar to the estimates from families ascertained through population-based studies (P for difference = .41). On the basis of the combined data, the estimated risks to age 80 years were 53% (95% CI, 44% to 63%) for female breast cancer, 5% (95% CI, 2% to 10%) for ovarian cancer, 2%-3% (95% CI females, 1% to 4%; 95% CI males, 2% to 5%) for pancreatic cancer, and 1% (95% CI, 0.2% to 5%) for male breast cancer. CONCLUSION These results confirm PALB2 as a major breast cancer susceptibility gene and establish substantial associations between germline PALB2 PVs and ovarian, pancreatic, and male breast cancers. These findings will facilitate incorporation of PALB2 into risk prediction models and optimize the clinical cancer risk management of PALB2 PV carriers. (C) 2019 by American Society of Clinical OncologyPeer reviewe

Cancer Surveillance Guideline for individuals with PTEN hamartoma tumour syndrome.

PTEN hamartoma tumour syndrome is a diverse multi-system disorder predisposing to the development of hamartomatous growths, increasing risk of breast, thyroid, renal cancer, and possibly increasing risk of endometrial cancer, colorectal cancer and melanoma. There is no international consensus on cancer surveillance in PHTS and all current guidelines are based on expert opinion. A comprehensive literature review was undertaken and guidelines were developed by clinicians with expertise from clinical genetics, gynaecology, endocrinology, dermatology, radiology, gastroenterology and general surgery, together with affected individuals and their representatives. Recommendations were put forward for surveillance for breast, thyroid and renal cancers. Limited recommendations were developed for other sites including endometrial, colon and skin. The proposed cancer surveillance recommendations for PHTS require a coordinated multidisciplinary approach and significant patient commitment. The evidence base for cancer surveillance in this guideline are limited, emphasising the need for prospective evaluation of the effectiveness of surveillance in the PHTS population