[Relationship between mutation at 1 573 fragment of TNF receptor II gene and keloid]

To study the mutations at 1 573 fragment of TNF receptor II (TNFR-II) gene in patients with keloid.

The tissue DNA was extracted from 22 samples of keloids donated by 22 patients (6 males and 16 females, aged 18-53 years), and all keloids were examined and classified by pathologist. The peripheral blood DNA was extracted from the same patients as the control. PCR was used to amplify the 1 573 fragment of TNFR-II gene from the keloid tissue DNA and peripheral blood DNA. The PCR products were sequenced directly and then compared with the GeneBank data.

All the concentration of the extracted DNA in trial were higher than 0.50 microg/microL and the purity (A260/A280) of the extracted DNA were higher than 1.5. It closed to the magnitude of the design DNA fragment by agarose gel electrophoresis examining, and corresponded with the test requirement. Mutations at 1 573 fragment of TNFR-II gene were detected in 13 out of 22 keloids. The mutation incidence was 59.1%. Among them, 9 had point mutation at codon 1 663, accounting 40.9%. No TNFR-II gene mutation was detected in all peripheral blood samples. There were significant difference between keloids DNA and peripheral blood DNA (P < 0.01). The mutations involved point mutation, deletion and insertion as well as multisite and multitype.

There is a correlation between the mutation at 1 573 fragment of TNFR-II gene and keloid.