CAT25 defines microsatellite instability in colorectal cancer by high-resolution melting PCR.

BACKGROUND: CAT25 (T25mononucleotide repeat of the Caspase 2 gene), is a promising DNA marker for detecting microsatellite instability (MSI) in colorectal cancer. CAT25 has the potential to be incorporated into the Bethesda panel, a commonly used panel of DNA microsatellites, or replace it in its entirety. We aimed to develop and validate a high-resolution melting-PCR (HRM-PCR) method for CAT25 instability detection in clinical samples. METHODS: The instability of CAT25, BAT25 (a poly(A) tract occurring in c-kit) and BAT26 (a poly(A) tract localized in hMSH2) microsatellites were assessed in DNA from tumour and peripheral blood obtained from 110 patients with colorectal cancer using HRM-PCR and capillary electrophoresis. Immunohistochemistry (IHC) staining for MSH2, MSH6, MLH1, and PMS2 enzymes was performed on tumours with jigj MSI. Allelic size variation of CAT25 was analysed on peripheral blood DNA from 208 healthy volunteers. RESULTS: The HRM-PCR for CAT25 was validated in clinical samples. CAT25 showed a tight range of 64-66 base pairs. Of 110 tumours, 11 had High MSI, later confirmed by IHC. CAT25 defines MSI alone as well as when used together with BAT25 and BAT26. CAT25 results provided 100% predictive values and p < 0.0001 to classify a tumour as having high MSI. CONCLUSIONS: We developed and validated a new HRM-PCR assay to detect CAT25 instability. Our findings showed a limited allelic size variation of CAT25 and highlighted to CAT25 as a promising marker for MSI analysis.

Homocysteine as a risk factor of restenosis after carotid endarterectomy.

AIM: Homocysteine (Hcy) has been identified as a potential risk factor for vascular disease. This study investigates the role of serum Hcy as clinical risk factor for restenosis after carotid endarterectomy (CEA). METHODS: In a prospective design, we studied patients who underwent carotid endarterectomy with venous patch closure technique with respect to alterations of Hcy levels pre and postoperatively. The patients studied were subjected to reevaluation for possible restenosis at time-points 3, 6, 9, 12, 18 and 24 months postoperatively. RESULTS: Fifty-three symptomatic and 37 asymptomatic patients with stenosis of internal carotid artery >70% were studied. Restenosis appeared in 7.25% of the patients within 24 months postoperatively. Hcy was the only parameter that correlated significantly with the presence of restenosis (P=0.010) and the presence of type VI (complicated) atheromatous plaque (P=0.005) within 24 months postoperatively. CONCLUSION: Hcy levels were found to be statistically significantly correlated with both the presence of complicated atheromatous plaque and the degree of internal carotid artery restenosis after CEA.