Clinicopathological Significance of ATM-Chk2 Expression in Sporadic Breast Cancers: a Comprehensive Analysis in Large Cohorts

ATM-Chk2 network is critical for genomic stability, and its deregulation may influence breast cancer pathogenesis. We investigated ATM and Chk2 protein levels in two cohorts [cohort 1 (n = 1650) and cohort 2 (n = 252)]. ATM and Chk2 mRNA expression was evaluated in the Molecular Taxonomy of Breast Cancer International Consortium cohort (n = 1950). Low nuclear ATM protein level was significantly associated with aggressive breast cancer including larger tumors, higher tumor grade, higher mitotic index, pleomorphism, tumor type, lymphovascular invasion, estrogen receptor (ER)−, PR−, AR−, triple-negative, and basal-like phenotypes (Ps b .05). Breast cancer 1, early onset negative, low XRCC1, low SMUG1, high FEN1, high MIB1, p53 mutants, low MDM2, low Bcl-2, low p21, low Bax, high CDK1, and low Chk2 were also more frequent in tumors with low nuclear ATM level (Ps b .05). Low ATM protein level was significantly associated with poor survival including in patients with ER-negative tumors who received adjuvant anthracycline or cyclophosphamide, methotrexate, and 5-fluorouracil–based adjuvant chemotherapy (Ps b .05). Low nuclear Chk2 protein was likely in ER−/PR−/AR−; HER-2 positive; breast cancer 1, early onset negative; low XRCC1; low SMUG1; low APE1; low polβ; low DNA-PKcs; low ATM; low Bcl-2; and low TOPO2A tumors (P b .05). In patients with ER+ tumors who received endocrine therapy or ER-negative tumors who received chemotherapy, nuclear Chk2 levels did not significantly influence survival. In p53 mutant tumors, low ATM (P b .000001) or high Chk2 (P b .01) was associated with poor survival. When investigated together, low-ATM/high-Chk2 tumors have the worst survival (P = .0033). Our data suggest that ATM-Chk2 levels in sporadic breast cancer may have prognostic and predictive significance

Association of common ATM variants with familial breast cancer in a South American population

Background: The ATM gene has been frequently involved in hereditary breast cancer as a low-penetrance susceptibility gene but evidence regarding the role of ATM as a breast cancer susceptibility gene has been contradictory. Methods: In this study, a full mutation analysis of the ATM gene was carried out in patients from 137 Chilean breast cancer families, of which 126 were BRCA1/2 negatives and 11 BRCA1/2 positives. We further perform a case-control study between the subgroup of 126 cases BRCA1/2 negatives and 200 controls for the 5557G > A missense variant and the IVS38-8T > C and the IVS24-9delT polymorphisms. Results: In the full mutation analysis we detected two missense variants and eight intronic polymorphisms. Carriers of the variant IVS24-9delT, or IVS38-8T > C, or 5557G > A showed an increase in breast cancer risk. The higher significance was observed in the carriers of IVS38-8T > C (OR = 3.09 [95% CI 1.11-8.59], p = 0.024). The IVS24-9 T/(-T), IVS38-8 T/C, 5557 G/A composite genotype confered a 3.19 fold increase in breast cancer risk (OR = 3.19 [ 95% CI 1.16-8.89], p = 0.021). The haplotype estimation suggested a strong linkage disequilibrium between the three markers (D' = 1). We detected only three haplotypes in the cases and control samples, some of these may be founder haplotypes in the Chilean population. Conclusion: The IVS24-9 T/(-T), IVS38-8 T/C, 5557 G/A composite genotype alone or in combination with certain genetic background and/or environmental factors, could modify the cancer risk by increasing genetic inestability or by altering the effect of the normal DNA damage response

Optimalizovaná metoda oplachu zvyšující účinnost odstraňování reziduí vysoce viskózních a barevných vzorků během BCOP (Bovine Corneal Opacity and Permeability) testu

Two modifications of the rinsing procedure within the BCOP assay were proposed. Their ability to enhance the removal efficiency of highly viscous and colored samples was compared with an unmodified BCOP procedure (TG OECD 437). The first modification consisted of three-step washing of the applied chemicals from the cornea using Eagle's Minimum Essential Medium (EMEM), olive oil and EMEM, while the classical OECD TG 437 procedure prescribes only EMEM. Within the second modification, mechanical removal of the tested sample from the cornea surface prior to the two step washing procedure was performed. The in vitro irritation score (IVIS) exceeded the value of 55 for 9 out of 20 samples when a non-modified rinsing procedure was used. The first modification with the olive oil resulted in a decrease in MS for numerous samples, while an IVIS score drop below the threshold value of 55 was only observed for two of them. Mechanical removal of sample residua resulted in a further decline in the measured IVIS. Only the three samples treated by means of this procedure revealed an IVIS above 55. The decreases in IVIS observed during both modifications were mainly related to the reduced opacity, whereas the permeability mostly remained unaffected. (C) 2015 Elsevier Ltd. All rights reserved.V článku jsou popsány dvě modifikace oplachu rohovky během BCOP testu, které zvyšují účinnost odrstraňování reziduí vysoce viskózních a barevných vzorků během testu oční dráždivosti a leptavosti prováděného v souladu se směrnicí TG OECD 437. První modifikace sestává z třístupňového oplachu za použití EMEM (Eagle's Minimum Essential Medium ), olivového oleje a EMEM, v rámci druhého postupu je pak ještě tomuto postupu předřazeno mechanické odstranění vzorku pomocí bavlněného tamponu. Oba procesy vedou k podstatnému poklesu měřeného IVIS skore pro celou řadu vysoce viskózních a barevných vzorků