Translational medicine of colorectal cancer / 中华胃肠外科杂志

Translational medicine is a systemic project because it is patient and clinical problems oriented, aiming at research results application, and involves multidisciplinary cooperation. Studies on molecular events in the precancerous stage, early stage and metastasis of colorectal cancer (CRC) are the CRC hot research topics currently. Investigations on the earliest molecular events can help to find out the markers which may improve the effect of CRC screening and predict CRC liver metastasis and prognosis. Based on the concept of micro environment, molecular targeted drugs to interfere with metastasis and invasion and new concepts of surgical resection margin and neoadjuvant therapy will gain recognition from clinicians.

K-ras gene mutation in colorectal cancer and its clinicopathologic significance / 中华外科杂志

<p><b>OBJECTIVE</b>To establish a simple, rapid and economical method in detecting mutations of oncogene K-ras and to investigate its mutations in colorectal cancer tissues and its relationship with clinicopathologic characteristics of colorectal carcinoma.</p><p><b>METHODS</b>Forty colorectal cancer tissues were tested for K-ras mutations at codon 12 and codon 13 using polymerase chain reaction (PCR) followed by direct sequencing and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) followed by sequence analysis. The other 113 colorectal cancer tissues were tested for K-ras mutations at codon 12 and codon 13 using PCR-RFLP followed by sequence analysis only. The mutation results were analyzed with the corresponding clinical pathological data.</p><p><b>RESULTS</b>Among 40 colorectal cancer cases, none of K-ras mutations at codon 12 and codon 13 was detected by PCR followed by direct sequencing. However, K-ras mutations were found in 11 cases (11/40, 27.5%) by PCR-RFLP followed by sequence analysis, including 8 cases at codon 12 and 3 cases at codon 13 respectively. Among 153 colorectal cancer cases, point mutations were detected by PCR-RFLP followed by sequence analysis in 58 cases (37.9%). Point mutations at codon 12 were found in 46 cases and 12 cases at codon 13. Mutations with the highest frequency were G→A transitions (25/58, 43.1%) at codon 12. No significant correlation was observed between mutations of K-ras and gender, invasive depth, tumor differentiation, number of invaded lymph nodes, distant metastasis and clinical stage (P > 0.05). Mutation of oncogene K-ras at codon 12 and codon 13 was closely related with age and tumor location (P < 0.05). The incidence of K-ras mutation was significantly higher in younger patients and in patients with ascending colon cancer.</p><p><b>CONCLUSIONS</b>PCR-RFLP followed by sequence analysis is a rapid, simple, sensitive and low-cost method. It is a suitable technology for detecting hot-spot mutations in the K-ras oncogene. Mutation of oncogene K-ras at codon 12 and codon 13 is a common molecular event in colorectal carcinogenesis, which might be related with age and tumor location.</p>