Japanese journal of cancer research : Gann最新文献

Werner syndrome (WS), adult progeria, is more common in Japan than elsewhere. It predisposes to osteosarcoma (OS) and five other rare tumors. To determine if and how OS is atypical in this genetic disorder, we studied the characteristics of ten Japanese cases with respect to clinical features, pathology, and radiographs, and compared them with a hospital series of 36 skeletal OS with the same atypical age-range, 35 - 57 years. The anatomic sites were also atypical: seven ankle / foot, two radius and one patella compared with only one at the ankle in the hospital series. The osteoblastic cell-type was about equally frequent in both series, but, among others than the three major subtypes, there was only one in WS as compared with 14 (39%) in the hospital series. The types of mutations were sought in five WS cases with OS. One showed no mutation at any of the ten known loci for Japanese, two were of type 4 / 4 and two of type 6 / 6. The mutations 4 and 6 have been found in 66% of alleles of WS cases in Japan. The increased frequency and unusual age and site distributions of OS in WS may be due to increased susceptibility, related to later-life leg ulcers, and weight-bearing on spindly ankles weakened by severe loss of lower limb subcutaneous tissue.

Recently, the CHK2 gene was identified as being a candidate gene responsible for Li-Fraumeni syndrome (LFS). Gastric cancer is often clustered in families with LFS, so it is possible that germline CHK2 mutation is also present in familial gastric cancer (FGC). We therefore defined the genomic structure of the CHK2 gene, designed intronic primers, and searched for germline CHK2 mutations in 25 FGC cases by polymerase chain reaction-single strand conformational polymorphism analysis of the entire coding region. In all of the 25 cases, at least two siblings had histories of gastric cancer. There were no FGC cases that showed germline CHK2 mutations. Thus, it was indicated that germline CHK2 mutations do not contribute to the familial clustering of gastric cancer.

A novel PCR method using confronting two-pair primers, named PCR-CTPP, is introduced to detect a single nucleotide polymorphism (base X or Y). One primer for the X allele is set to include X' at the 3' end (antisense), where X' is the antisense of X, with the counterpart sense primer upstream. For the Y allele, a sense primer including Y at the 3' end is set, with the antisense primer downstream. One common band and one specific band for each allele are amplified, which allows genotyping directly by electrophoresis. This method is exemplified by application to the polymorphisms of beta-adrenoceptor 2 and interleukin 1B. It is simpler than PCR-RFLP (restriction fragment length polymorphism), which requires incubation with a restriction enzyme, and is suitable for genotyping in studies of genetic epidemiology involving hundreds of samples.

A modified AFLP (amplified fragment length polymorphism) method was employed to isolate genes differentially expressed in renal carcinogenesis of Tsc2 gene mutant (Eker) rats. One gene, selected for further investigation, was named "Niban" "second" in Japanese), because it is the second new gene to be found after Erc (expressed in renal carcinoma) in our laboratory. Importantly, "Niban" is well expressed even in small primary rat Eker renal tumors, more than in progressed cell lines, and is also expressed in human renal carcinoma cells, but not in normal human or rat kidneys. Chromosome assignment was to RNO 13 in the rat, and HSA 1. This "Niban" gene is a candidate as a marker for renal tumor, especially early-stage renal carcinogenesis.