CDKN1B 109VG and CDKN2A (540CG & 580CT) polymorphisms and susceptibility to colorectal cancer: A case-control study of the Iranian population
GENE REPORTS
Authors: Gohari, Nazanin; Saadat, Iraj
Abstract
Background: One of the most important factors leading to tumorigenesis is abnormality in the cells proliferation, because of the irregularity in cell cycle progression. CDKN2A (p16) and CDKN1B (p27) are tumor suppressors and regulators of cell cycle at G1 and G1-S transition. Any disorders in activity or expression of these two tumor suppressors can cause cancer. Aims: In this study, we appraised the relationship between 3 polymorphisms: p27 109VG (rs2066827) in exon1 and p16 [540CG (rs11515), 580CT (rs3088440)] in 3'UTR with the risk of colorectal cancer susceptibility in Iranian population. Subjects and methods: This case-control study was carried out on 214 cases with CRC and 233 control subjects. For p27 109VG and p16 (540CG, 580CT) genotyping, PCR-RFLP technique was used. Results: Logistic regression analysis revealed that G allele of p16 540CG significantly decreased the risk of CRC (OR = 0.63, CI = 0.42- 0.95, P = 0.031), but subjects with TT genotype of 580CT are more likely to develop CRC (OR = 4.63, CI = 1.28-16.71, P = 0.019). There were no significant relationships with p27 109VG and haplotype of p16 (540CG, 580CT) with CRC risk in Iranian population. However, coincidence in VG genotype of p27 109VG and CC genotype of p16 540CG has significantly increased the susceptibility to colorectal cancer (OR = 2.02, CI = 1.02-3.98, P = 0.042). Conclusion: This study indicates that the p16 [540CG (rs11515), 580CT (rs3088440)] polymorphisms are associated with the risk of CRC in Iranian population.
Genetic testing for hereditary hyperparathyroidism and familial hypocalciuric hypercalcaemia in a large UK cohort
CLINICAL ENDOCRINOLOGY
Authors: Mariathasan, Sashi; Andrews, Katrina A.; Thompson, Edward; Challis, Ben G.; Wilcox, Sarah; Pierce, Heather; Hale, Julia; Spiden, Sarah; Fuller, Gavin; Simpson, Helen L.; Fish, Brian; Jani, Piyush; Seetho, Ian; Armstrong, Ruth; Izatt, Louise; Joshi, Mamta; Velusamy, Anand; Park, Soo-Mi; Casey, Ruth T.
Abstract
Background Primary hyperparathyroidism (PHPTH) is a common endocrine disorder and an estimated 10% of cases are hereditary, related to syndromes including; multiple endocrine neoplasia (MEN) type 1, MEN type 4, MEN2A and hereditary hyperparathyroidism-jaw tumour syndrome. Establishing the underlying genetic cause for PHPTH allows for personalized and cost-effective management. Familial hypocalicuric hypercalcaemia (FHH) is a benign disorder of hypercalcaemia associated with an inappropriately low urinary calcium excretion, which is quantified by the calcium creatinine clearance ratio (CCCR). Recent NHS England National Genomic Test Directory testing criteria for familial hyperparathyroidism state testing patients presenting with PHPTH and CCCR > 0.02 presenting (i) <35 years of age, or (ii) <45y with one of (a) multiglandular disease, or (b) hyperplasia on histology, or (c) ossifying fibroma(s) of the maxilla and/ or mandible, or (d) a family history of unexplained PHPTH. The testing criterion for FHH is a CCCR MEN1, CDC73, CASR, CDKN1A, CDKN1B, CDKN2B, CDKN2C, RET, GCM2, GNA11, andAP2S1in NHS-accredited Regional Genetic laboratories. Aims of this study were to better define testing criteria for suspected hereditary PHPTH in a UK cohort. Results A total of 121 patients were included in this study (92 female) with a mean age of 41 years (SD 17). A pathogenic germline variant was identified in 16% (n = 19). A pathogenic variant was identified in the PHPTH genesCDC73in a single patient andMEN1in six patients (6% of total), in the FHH genes,CASRin 11 patients andAP2S1in a single paediatric case (10% of total). A variant of uncertain significance (VUS) was identified in eight patients (6%) but over the course of this study familial segregation studies and computational analysis enabled re-classification of four of the variants, with two VUS's in theCASRgene being upgraded to likely pathogenic variants. Age at diagnosis and multiglandular disease as sole risk factors were not predictive of a pathogenic germline variant in this cohort but a positive family history was strongly predictive (P = .0002). A significant difference in the mean calcium creatinine clearance ratio (CCCR) in those patients with an identifiedCASRpathogenic variant versus those without (P = .0001) was demonstrated in this study. Thirty-three patients were aged over 50 years and the diagnostic rate of a pathogenic variant was 15.1% in those patients >50 years of age compared to 15.9% in those 50 years and with a CCCR of <0.01, were diagnosed with a pathogenic variant inCASR. Conclusion Family history was the strongest predictor of hereditary PHPTH in this cohort. This study has highlighted the importance of re-evaluating VUS's in order to inform patient management and enable appropriate genetic counselling. Finally, this study has demonstrated the need to consider genetic testing for PHPTH in patients of any age, particularly those with additional risk factors.