The Clinical Significance Of The Detection Of Homozygous Deletion Of P16 Gene In Pleural Effusion

Objective To establish the analysis method of multiple tumor suppressor gene or p16 gene and explore the clinical significance of homozygous deletion of p16 gene in pleural effusion. Method The cDNA of p16 exon2 was obtained by reverse transcription-polymerase chain reaction (RT-PCR) with human Hela cells as templates. The pGEM-p 16 was constructed by inserting the cDNA of p16 exon2 into pGEM-T. The recombinant DNA was transformed into the XL 1-Blue, which was proved by restrictive endonuclease mapping and the eDNA of p16 exon2 from American Cold Spring Harbor Lab. The recombinant plasmid was amplified by culture ,purified, and cut off with EcoR 1. The cDNA of p16 exon2 obtained by purifying was used as a probe labeled with Digoxin. According to the published p16 gene sequence, the primers of p16 exonl,exon2,and CDK4 were designed. CDK4 was served as a internal control. The specific amplified products were achieved by PCR. The CDK4 amplified product appeared without PCR product of p16 gene was seen as the deletion of p16 exonl or exon2. Result Neither homozygous deletion of p16 gene exonl and exon2 in 21 tuberculosis pleural effusion samples nor homozygous deletion of p16 gene exonl in 31 malignant pleural effusion samples was found. The homozygous deletion of p16 gene exon2 was detected in 12 samples from 31 malignant pleural effusions, whose positive rate was 38.7%(1213 1). In the meantime, these samples were analyzed by the exfoliated cytology. The positive samples were detected in 16 of them, whose positive rate was 51 .62%(1613 1). Using both of above method, the positive rare could be enhanced from 51.62%(16131) to 70.97%(2213 1). Conclusions Our present data suggest that the specifity of diagnosis on malignant pleural effusion was 100% with the detection of p16 gene homozygous deletion. The combining examinations of exfoliated cytology with homozygous deletion of p16 exon2 in pleural effusion can not only increase the positive rate of diagnosis in malignant pleural effusion, but also recruit and enhance the diagnostic value of conventional pleural cytology.