ObjectiveTo determine the frequency and type of p16 gene homozygous deletion and mutation with the progression of human gastric carcinogenesis.MethodsPCR （polymerase chain reaction），SSCP (single strand conformation polymorphism) and DNA sequencing were performed on 50 operative tissues, which included 7 early gastric cancer and 43 advanced gastric cancer. In this group there were 36 male and 14 female patients aged 35 to 68,which included 30 welldifferetiated adenocarcinoma and 20 poordifferentiated carcinoma; 19 patients with lymph node metastases.ResultsTotal mutation frequency of p16 gene was 8.00%(4/50), including 14.29%(1/7) of early cancer and 7.00%(3/43) of advanced cancer，there was no significant difference between early and advanced cancer （P＞0.05）. In addition, p16 gene mutation was not related to site，location，grade of tumor differentiation and lymph node metastases, respectively. Total deletion frequency of p16 gene was 16.00%(8/50), of which 18.60%(8/43) was detected in advanced cancer, but no cases in early cancers. There was a significant difference between early and advanced cancer （P＜0.05）, and frequency p16 gene homozygous deletion was related to grade of tumor differentiation and lymph node metastases, respectively. Direct DNA sequencing displayed that 4 point mutations detected in 99,125,433,441 base, there were 3 missense mutation and 1 samesense mutation, no deletion or insertion was found. Conclusionp16 gene mutation is an early event in gastric carcinogenesis，it helps early diagnosis of human gastric carcinoma. p16 gene homozygous deletion is a late event in gastric carcinogenesis，it might relate to metastases and recurrence of gastric cancer.
Objective To compare the differences of chromosome aberration and Rb 1 gene mutation among 3 cloned cells of SO-Rb50 cell line of retinoblastoma. Methods 1.Three cell cloned strains named MC2, MC3, MC4 were isolated from SO-Rb50. 2. Gbanding and karyotype analysis were performed on the llth passage cells of the 3 cell strains.3.All exons and the promoter region of the Rb gene were detected by PCR-SSCP analysis in tumor cell DNA extracted from the 3 cell strains. Results 1.Both numerical and structural chromosomal aberrations could be observed in these 3 cell strains.Several kinds of structural chromosomal aberrations were observed.The chromosome aberrations in the same passage of different cell strains were different.Aberration of chromosome 13 was rare and the aberration feature was different in the 3 cell strains.Five marker chromosomes were identified.M1,t(1;1)qter-p35∷q24-ter could befound in all cell strains.Two of them M4 and M5,have not been reported in SO-Rb50 cell line previously.2.SSCP analysis of exon 24 showed that MC411 and MC3138 had abnormal band. Conclusions The characteristics of heterogeneity of the original tumor cell line SO-Rb50are still kept during a long-term culture in vitro and the cloned strains had dynamic changes during this period.Aberration of chromosome 13 is not the only cause of RB;aberration of chromosome 1,a commom event in some neoplasias as well as in SO-Rb50, plays a meaningful role in the immortalization of this cell line. (Chin J Ocul Fundus Dis, 1999, 15: 146-148)
Mutations in the BEST1 gene are associated with a range of retinal diseases collectively referred to as "Best diseases", including Best vitelline macular dystrophy. More than 300 mutations at different sites of the BEST1 gene have been found, which may cause a series of functional disorders such as the mistransport of the calcium-activated anion channel protein-1 protein encoded by it, protein oligomerization defects, and abnormal anion channel activity, leading to different clinical phenotypes. Although it has been established that the BEST1 gene mutation is associated with at least one different type of Best disease, the relationship between the specific gene mutation site and the specific clinical phenotype has not been fully defined. For the time being. Drugs and gene therapy for the Best diseases are still in the basic research stage, which provides a broad development space for future treatment exploration. In the future, when selecting gene therapy in clinical applications, it is necessary to combine the clinical phenotype and molecular diagnosis of patients, and clearly define their mutation types and pathogenic mechanisms in order to achieve better personalized treatment effects.
Objective To observe the molecular genetic characteristics of seven Chinese families with Leberprime;s hereditary optic neuropathy (LHON). Methods Ophthalmologic examinations were performed on seven probands, maternal members from seven Chinese families and 134 healthy controls. There were two LHON patients in seven Chinese families except probands. The entire mitochondrial genome was amplified using 24 pairs of oligonucleotide primers with overlapping fragments.The mutational site was analyzed through comparison of the Results and Cambridge reference sequence. The penetrance of mutation site was calculated and the haplotype was analyzed. Results Molecular analysis of mitochondrial DNA (mtDNA) in these pedigrees revealed the absence of three common LHON associated with ND4 G11778A, ND1 G3460A and ND6 T14484C mutations. The ND1 T3394C mutation in probands and other matrilineal relatives was present in four out of 134 Chinese healthy controls. Strikingly, these families exhibited very low penetrance of visual impairment. The penetrance was 12.50%, 22.22%, 16.76%, 6.25%, 9.09%, 11.11% and 28.57%. The Results of phylogenetic tree analysis of submitochondrial haplotype showed that these mtDNA polymorphism sites belong to the Asian haplogroups M9, M9, M, D4, M, M9 and M9. Conclusions T3394C mutation exists in seven Chinese LHON pedigrees, and the penetrance was ranged from 6.25% to 28.57%. The patients have different clinical manifestations.
Tyrosine kinase inhibitors (TKIs) are the standard of care for non-small cell lung cancer patients with epidermal growth factor receptor (EGFR) mutation. The efficacy of TKIs and prognosis of EGFR-mutated patients with compound EGFR mutation, oncogene mutation, suppresser gene mutation or other diver gene mutation are worse than those of patients with a single EGFR mutation. This article makes a review of related clinical researches aiming to provide references for clinical scenarios. To sum up, molecular alterations and clinical features should be correlated as accurately and dynamically as possible in the diagnostic and therapeutic process, and combined therapeutic strategies should be chosen flexibly and reasonably to improve patients’ survival and prognosis.
Objective To investigate the spectrum of mitochondrial DNA (mtDNA) mutations in Chinese patients with Leber′s hereditary optic neuropathy (LHON). Methods The primary mtDNA mutations (G3460A、G11778A and T14484 C) of 140 patients with LHON were detected by mutation-specific priming polymerase chain reaction (MSP-PCR), heteroduplex-single strand conformation polymorphism polymerase chain reaction (HA-SSCP), restriction fragment length polymorphisms (RFLP) and measurement of DNA sequence. The transmissibility of the patients′ stirps was analyzed.Results In the 140 patients with LHON, G11778A mtDNA primary mutation was found in 130 (92.9%), including 113 males and 17 females; G3460A mutation was found in 2 (1.4%) including 1 male and 1 female; G14484A mutation was found in 8 (5.7% ) including 6 males and 2 females.Conclusion In Chinese patients with LHON, the incidence of G11778A mtDNA mutation is higher than that of G3460A and T14484C. (Chin J Ocul Fundus Dis，2003，19：269-332)