Detection of chromosomal translocations involving ALK gene in anaplastic large cell lymphoma by fluorescence in-situ hybridization and its clinical significance / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate clinicopathologic features and clinical value of the chromosomal translocation involving anaplastic lymphoma kinase (ALK) in anaplastic large cell lymphoma (ALCL) by fluorescence in situ hybridization (FISH).</p><p><b>METHODS</b>A total of 55 cases, including 45 cases of ALCL and 10 reactive lymphoid hyperplasia, were collected during 1999 to 2006 in the Department of Pathology, Fudan University Shanghai Cancer Center, and Xinhua Hospital Affiliated to Shanghai Jiaotong University. All cases were studied by FISH using dual color break apart probes of ALK for detection of chromosomal translocation, compared with the previous results of immunohistochemistry (IHC) and reverse-transcriptase polymerase chain reaction (RT-PCR) for the detection of ALK aberrations.</p><p><b>RESULTS</b>The result of FISH showed that the clear red and green fluorescence signals were detected in 38 cases of ALCL, in which conspicuous split signals were observed in tumor cells in 24 cases (63.2%), suggesting the rearrangement of the ALK locus, with multiple copies of ALK gene in one case. In addition, the rearrangement of the ALK locus was not identified in 14 of 38 cases (36.8%); and the FISH results were unable to be evaluated in 7 cases, because no fluorescent signals involving ALK gene were found or signals were too weak to be analyzed. The concordance for the detection ALK aberrations in ALCL between FISH and RT-PCR, FISH and IHC were both statistically significant (P < 0.01). Chromosomal translocation involving ALK gene was not found in all 10 cases of reactive lymphoid hyperplasia.</p><p><b>CONCLUSIONS</b>ALCL is an entity of lymphoma characterized by special clinical presentation, morphology, and ALK aberrations. FISH is helpful for detection of the chromosomal translocations involving ALK in ALCL, however, the detection efficiency by FISH may be affected by storage time of the paraffin-embedded tissue; and therefore combined detection with IHC and RT-PCR could complement each other and help for differential diagnosis of ALK(+)ALCL from ALK(-)ALCL.</p>

KRAS and BRAF gene mutations in correlation with clinicopathologic features of colorectal carcinoma in Chinese / 中华病理学杂志

<p><b>OBJECTIVE</b>To retrospectively analyze KRAS and BRAF gene mutation features in Chinese colorectal cancer (CRC) and their clinicopathologic relationship.</p><p><b>METHODS</b>557 colorectal cancer cases were collected, including 325 colon cancer and 232 rectal cancer. PCR amplification and DNA sequencing were used to detect mutations in exon 2 of KRAS gene and exon 15 of BRAF gene mutation.</p><p><b>RESULTS</b>(1) KRAS mutation was found in 40.4% (225/557) colorectal cancer. The most common mutation locations were in codon 12(79.1%, 178/225) and codon 13 (20.4%, 46/225). The most common mutation types were GGT > GAT (G12D) (37.8%, 85/225), GGT > GTT(G12V) (20.0%, 45/225) in codon 12 and GGC > GAC (G13D) in codon 13 (19.6%, 44/225). These three point mutations accounted 77.3% (174/225) in total KRAS gene mutation cases. All cases showed only one of point mutation types. (2) Among 557 CRC cases, KRAS mutation was significantly higher in female (46.2%, 92/199) than in man (37.2%, 133/358; P < 0.05). KRAS gene codon 13 mutation was higher in right colon cancer (11.3%, 12/106) than that in left colon cancer (4.8%, 6/124), but it didn't show any statistical significance (P > 0.05). (3) BRAF gene mutation was 5.1% (10/197) in colorectal cancer and 8/10 were the point mutation of GTG > GAG (V600E). Eight colorectal cancer cases with GTG > GAG (V600E) were not showing KRAS gene mutation. Both two cases with mutation on codon 600 (GTG > ATG, V600M) and codon 606 (GGG > AGT, G606S) showed codon 12 mutation of KRAS gene. (4) BRAF (V600E) gene mutation was higher in female (8.5%, 6/71) than that in male (1.6%, 2/126; P = 0.05); BRAF mutation in colon cancer (8.3%, 6/72) was higher than that in rectum cancer (2.1%, 2/94), but hadn't statistical significance (P > 0.05).</p><p><b>CONCLUSIONS</b>(1) Codon 12, 13 in KRAS gene and codon 600 in BRAF gene are the most common mutation points in Chinese colorectal cancer. KRAS and BRAF mutations are mutually exclusive. (2) KRAS and BRAF gene mutation is higher in female than that in male, suggesting that RAS-RAF-MAPK signal pathway is probably related to hormones directly or indirectly. (3) There is a trend that codon 13 mutation in KRAS and codon 600 mutation in BRAF in right colon cancer are higher than that in left colon cancer, respectively, however, which needs more cases to be further verified.</p>

Study on the germline mutation of MSH6 gene in Chinese hereditary nonpolyposis colorectal cancer pedigrees using PCR based sequencing / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To detect the germline mutation of mismatch repair gene (MSH6) in hereditary nonpolyposis colorectal cancer (HNPCC) kindreds fulfilling different clinical criteria.</p><p><b>METHODS</b>The germline mutations of MSH6 gene were detected by PCR based DNA sequencing in 39 unrelated HNPCC probands fulfilling different clinical criteria in which MSH2 and MLH1 mutations were excluded. The exons with missense mutations were analyzed using PCR sequencing in the germline genomic DNA of 137 healthy persons. The expression of MSH6 protein was detected by Envision immunohistochemistry staining in the tumor tissues of the mutational probands.</p><p><b>RESULTS</b>Six germline mutations of MSH6 gene were detected in 39 probands of Chinese HNPCC kindreds, and the mutations distributed in the exon 4, 6, 9 and 10. Four out of six mutations were missense mutation, one was nonsense mutation and the remaining one was insertion mutation in splice site. The results of sequecing for the exons with above four missense mutations in 137 healthy persons' genomic DNA showed that 5 of 137 persons had the missense mutation of c.3488 A to T at codon 1163 of the 6th exon. The mutational rate was approximately 3.65% (5/137), so the mutation could be a single nucleotide polymorphism (SNP). The remaining missense mutations were not found in any germline genomic DNA of 137 healthy persons. Positive expression of MSH6 protein had been identified in the tumor of the SNP proband while the tumors had negative MSH6 protein expression in the rest probands of germline mutation MSH6 gene. The types of mutations and their potential significance were determined by comparing the following databases: http://www.ncbi.nlm.nih.gov/, http://www.ensembl.org/homo-sapies, and http://www.insight-group.org. Five out of the six mutations had not been reported previously and they were new pathological mutations, the rest one was a new SNP.</p><p><b>CONCLUSION</b>Germline mutations of MSH6 gene may play an important role in Chinese HNPCC kindreds fulfilling different clinical criteria. It is necessary to analyze the germline mutations of MSH6 gene using sequencing to identify HNPCC families in the probands in which MSH2 and MLH1 mutation were excluded.</p>

Detection of chromosomal aberration in paraffin-embedded synovial sarcoma tissues by fluorescence in-situ hybridization / 中华病理学杂志

<p><b>OBJECTIVE</b>To evaluate the application of fluorescence in-situ hybridization (FISH) in detection of gene translocation in paraffin-embedded tissue samples of synovial sarcoma.</p><p><b>METHODS</b>Interphase FISH was carried out in paraffin-embedded tissue of 42 cases of synovial sarcoma and 9 cases of non-synovial sarcoma, using a LSI SYT (18q11.2) dual color break-apart probe. In all of the cases studied, the gene fusion product SYT-SSX was also analyzed by reverse transcription-polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>Positive signals were detected in 37 cases (88.1%) of synovial sarcoma by FISH, as compared with 35 cases (83.8%) by RT-PCR and 39 cases (92.9%) by both techniques. Of the 39 positive cases, 33 cases (78.5%) revealed SYT gene translocation.</p><p><b>CONCLUSIONS</b>FISH may serve as an adjunctive diagnostic tool in problematic cases of synovial sarcoma and can be applied in paraffin-embedded tissue samples. As compared with RT-PCR, FISH is also sensitive and reliable. The methodology is less labor intensive and time consuming. FISH has great potential in molecular diagnosis of soft tissue tumors.</p>

Application and evaluation of biologic potential grading criteria for localized gastrointestinal stromal tumors / 中华病理学杂志

<p><b>OBJECTIVE</b>To evaluate the implication of Fletcher and Miettinen biologic potential grading criteria in native localized gastrointestinal stromal tumors (GISTs).</p><p><b>METHODS</b>Two hundred and twenty localized GISTs with complete clinicopathologic and follow-up data were evaluated for their biologic potential by Fletcher and Miettinen grading criteria. The implication of the two grading criteria were compared by survival analysis.</p><p><b>RESULTS</b>Evaluated by Fletcher grading criteria, the overall and disease-free survival rate of high risk GISTs was lower than that of very-low, low and intermediate GISTs; while the overall and disease-free survival rate of very-low, low and intermediate risk GISTs had no statistical diffence. In the high risk GISTs, the overall and disease-free survival rate of small intestinal and rectal GISTs was lower than that of gastric GISTs; while in the intermediate risk GISTs, the disease-free survival rate of small intestinal GISTs was lower than that of gastric GISTs. Evaluated by Miettinen grading criteria, the overall and disease-free survival rate of high risk GISTs was lower than that of very-low, low and intermediate GISTs; while the overall and disease-free survival rate of very-low, low and intermediate risk GISTs had no statistical difference. In the risk subgroup of GISTs, the overall and disease-free survival rate of gastric, small intestinal and rectal GISTs had no statistical difference.</p><p><b>CONCLUSIONS</b>Fletcher grading criteria is simple and easy to use; while Miettinen grading criteria for evaluating biological potential by anatomic site is more critical and has important reference implication for the selection of high risk patients for targeted adjuvant treatment.</p>