Assessment of genetic mutations in the XRCC2 coding region by high resolution melting curve analysis and the risk of differentiated thyroid carcinoma in Iran

Homologous recombination (HR) is the major pathway for repairing double strand breaks (DSBs) in eukaryotes and XRCC2 is an essential component of the HR repair machinery. To evaluate the potential role of mutations in gene repair by HR in individuals susceptible to differentiated thyroid carcinoma (DTC) we used high resolution melting (HRM) analysis, a recently introduced method for detecting mutations, to examine the entire XRCC2 coding region in an Iranian population. HRM analysis was used to screen for mutations in three XRCC2 coding regions in 50 patients and 50 controls. There was no variation in the HRM curves obtained from the analysis of exons 1 and 2 in the case and control groups. In exon 3, an Arg188His polymorphism (rs3218536) was detected as a new melting curve group (OR: 1.46; 95 percentCI: 0.432-4.969; p = 0.38) compared with the normal melting curve. We also found a new Ser150Arg polymorphism in exon 3 of the control group. These findings suggest that genetic variations in the XRCC2 coding region have no potential effects on susceptibility to DTC. However, further studies with larger populations are required to confirm this conclusion.

Central venous catheter detected on a routine Tc-99m MDP bone scan

A man was referred for a bone scan as part of investigation for left knee arthritis. Increased uptake in the region of the left knee was observed. Moreover, abnormal linear activities in the right border of sternum and right infraclavicular region were noted. These areas were initially interpreted as abnormal bony lesions. CXR confirmed presence of a catheter in the right brachiocephalic vein and superior vena cava and was determined that the abnormal scintigraphic findings were because of radiotracer adhesion to the indwelling central venous line[1,2]. Although it is a well-known fact for those who are familiar with nuclear medicine, but this case emphasizes again the importance of obtaining accurate clinical history prior to interpreting scintigraphic studies.