Molecular diagnosis and therapy for occult peritoneal metastasis in gastric cancer patients

To apply an individualized oncological approach to gastric cancer patients,the accurate diagnosis of disease entities is required.Peritoneal metastasis is the most frequent mode of metastasis in gastric cancer,and the tumor-node-metastasis classification includes cytological detection of intraperitoneal cancer cells as part of the staging process,denoting metastatic disease.The accuracy of cytological diagnosis leaves room for improvement;therefore,highly sensitive molecular diagnostics,such as an enzyme immunoassay,reverse transcription polymerase chain reaction,and virusguided imaging,have been developed to detect minute cancer cells in the peritoneal cavity.Molecular targeting therapy has also been spun off from basic research in the past decade.Although conventional cytologyis still the mainstay,novel approaches could serve as practical complementary diagnostics to cytology in near future.

Detection of Helicobacter pylori resistance to clarithromycin and fluoroquinolones in Brazil:A national survey

AIM To evaluate bacterial resistance to clarithromycin and fluoroquinolones in Brazil using molecular methods.METHODS The primary antibiotic resistance rates of Helicobacter pylori(H. pylori) were determined from November 2012 to March 2015 in the Southern,South-Eastern,Northern,North-Eastern,and Central-Western regions of Brazil. Four hundred ninety H. pylori patients [66% female,mean age 43 years(range: 18-79)] who had never been previously treated for this infection were enrolled. All patients underwent gastroscopy with antrum and corpus biopsies and molecular testing using Geno Type Helico DR(Hain Life Science,Germany). This test was performed to detect the presence of H. pylori and to identify point mutations in the genes responsible for clarithromycin and fluoroquinolone resistance. The molecular procedure was divided into three steps: DNA extraction from the biopsies,multiplex amplification,and reverse hybridization. RESULTS Clarithromycin resistance was found in 83(16.9%) patients,and fluoroquinolone resistance was found in 66(13.5%) patients. There was no statistical difference in resistance to either clarithromycin or fluoroquinolones(P = 0.55 and P = 0.06,respectively) among the different regions of Brazil. Dual resistance to clarithromycin and fluoroquinolones was found in 4.3%(21/490) of patients. The A2147 G mutation was present in 90.4%(75/83),A2146 G in 16.9%(14/83) and A2146 C in 3.6%(3/83) of clarithromycin-resistant patients. In 10.8%(9/83) of clarithromycin-resistant samples,more than 01 mutation in the 23 S r RNA gene was noticed. In fluoroquinolone-resistant samples,37.9%(25/66) showed mutations not specified by the Geno Type Helico DR test. D91 N mutation was observed in 34.8%(23/66),D91 G in 18.1%(12/66),N87 K in 16.6%(11/66) and D91 Y in 13.6%(9/66) of cases. Among fluoroquinolone-resistant samples,37.9%(25/66) showed mutations not specified by the Geno Type Helico DR test. CONCLUSION The H. pylori clarithromycin resistance rate in Brazil is at the borderline(15%-20%) for applying the standard triple therapy. The fluoroquinolone resistance rate(13.5%) is equally concerning.

Multiplex ligation-dependent probe amplification for rapid detection of deletions and duplications in the dystrophin gene

Objective：Duchenne muscular dystrophy （DMD） and Becker muscular dystrophy （BMD） are X-linked disorders caused by mutations in the dystrophin gene. The majority of recognized mutations are copy number changes of individual exons. The objective of the present study was to assess the multiplex ligation-dependent probe amplification （MLPA） effects of detection of gene mutations. Methods： Samples of 20 control males and 80 males and their mothers referred to our diagnostic facility on the clinical suspi- cion of DMD or BMD were tested by MLPA and multiplex PCR. Results ： The mean DQs for all peak of 20 control male samples was 1.02 （range from 0.83 to 1.21） by MLPA. Deletions or duplications were iden- tified in 6 out of 31 families that had been previously tested as negative by multiplex PCR. One case of complex rearrangement involving a duplication of two regions： dupEX3-9 and dupEX 17-41 were found by MLPA. Conclusions： MLPA is a highly sensitive method and rapid alternative to multiplex PCR for detec- tion of DMD and BMD.