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Mutations inCDH1, which encodes E-cadherin, have been associated with hereditary diffuse gastric cancer (HDGC) in Western populations but have not been shown to play a major role in Asians. Recently, a patient with familial gastric cancer (FGC) was shown to harbor a germline mutation in theTP53gene, which encodes p53 and has been previously associated with Li-Fraumeni Syndrome (LFS). To determine whether mutations inTP53are associated with FGC in Asians, we screened the entire coding region ofTP53in probands from 23 Korean FGC families. We identified a nonsense (E287X)TP53germline mutation in a family whose history is compatible with both HDGC and LFS. Two members of this family (SNU-G2) were afflicted with brain tumors, seven with gastric cancers, two with sarcomas, and one with both gastric cancer and a sarcoma. The E287XTP53mutation segregated with the cancer phenotype in the family members from whom DNA samples were available. To our knowledge, this is the first report of a large family with both HDGC and LFS. Our results suggest thatTP53mutational screening in FGC families should be interpreted with caution because additionalTP53mutation-carrying HDGC families may also show LFS-related phenotypes. [ABSTRACT FROM AUTHOR]

Microsatellite instability (MSI) plays an important biological role in various types of cancers, and especially in colorectal cancers. This study aimed to develop a simple, efficient, new method for robust MSI analysis. DNA was extracted from 175 (105 proximal colon and 70 distal colorectal) cancer samples and matched normal tissues, and five Bethesda microsatellite markers (BAT-25, BAT-26, D5S346, D2S123, and D17S250) were examined for MSI by denaturing high-performance liquid chromatography (DHPLC) analysis at a temperature of 50°C and a flow rate of 0.9 ml/min. It took just 9 min per PCR product to determine MSI or microsatellite stability (MSS) using the new protocol. The DHPLC results were confirmed with conventional gel-based electrophoresis and capillary-based sequencing method. Of 175 samples, 45 (26%) showed high micro-satellite instability (MSI-H), 12 (7%) showed low microsatellite instability (MSI-L), and 118 (67%) showed MSS. All MSI samples were deletion mutants and all 12 MSI-L cases had MSI in dinucleotide markers (D5S346, D2S123, and D17S250). MSI was significantly associated with proximal colon cancers (p<0.0001), as previously reported. The MSI-H tumors were also associated with tumor node metastasis (TNM) I/II stages (p=0.05) and high-grade tumors (p<0.01). Here, we propose a DHPLC-based method as an alternative for MSI analysis. [ABSTRACT FROM AUTHOR]