K-ras gene mutation status in colorectal cancer: comparative analysis of pyrosequencing and PCR-RFLP

Vol. 54 No. 3 Suppl., 2013
This supplement was not sponsored by Outside Organizations.


Maria Dobre, Maria Comanescu, D. Arsene, Cristina Iosif, G. Bussolati

Background: In patients with high-stage colorectal carcinomas (CRC), anti-EGFR therapy is known to be effective only in cases with a wild-type K-ras gene status. Different procedures have been proposed for such evaluation. Materials and Methods: The mutation status of K-ras gene, codons 12, 13 and 61 was determined in 250 CRC cases using the pyrosequencing assay. In addition, we compared the performance of the pyrosequencing procedure with that of PCR-RFLP in a subset (n=100) of the CRC samples the latter only in codons 12 and 13. Results: Using pyrosequencing, 46.4% of the 250 CRC cases were found mutated. Most mutations were located in codon 12 (36.4% from all cases) and several were located in codon 61 (3.2%). All mutation identified by PCR-RFLP were confirmed by pyrosequencing and, in addition, one more mutated sample was identified in the subset of 100 samples. Conclusions: Both methods are highly specific and can profitably be used in the molecular diagnosis of colorectal cancer in order to establish the adequate therapy.

Corresponding author: Maria Comanescu, MD, PhD; e-mail: mariacomanescu@yahoo.com

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Paula Perlea, Cristina Coralia Nistor, C. Toma, B. Dimitriu

The significant rate of failure of endodontic treatment to lower incisors was attributed to poor knowledge of their endodontic morphology. As emphasized by Tinelli ME et al. (2011), the morphology of the endodontic system is strongly related to ethnicity, making possible the existence of important anatomical variations at different population groups. The present study analyzes, using radiological means, the endodontic anatomy of lower incisors extracted from a Romanian population. Five hundred seventy-five lower central and lateral incisors were radiographed and Weine's classification was used to evaluate their endodontic morphology. After processing the data, it was concluded that 81% of the studied teeth have one canal and the remaining 19% have two canals. In terms of endodontic configuration, 81% of 575 studied teeth are Weine Type I, 17% Type II, 1% Type III and 1% Type IV. Results obtained in this study are within existing international endodontic literature. Type II and IV configurations have a high degree of treatment difficulty. This requires thorough clinical and radiological examination of several incidents, possibly cone beam computed tomography (CBCT) and individualized therapeutic means to ensure treatment success. This study is the first of this magnitude in the Romanian specialty literature.

Corresponding author: Paula Perlea, Assistant Professor, DMD, PhD; e-mail: paula.perlea@gmail.com

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