BACKGROUND-Oncogenic fusion genes consisting of EML4 and anaplastic lymphoma kinase (ALK) are present in a subgroup of non-small-cell lung cancers, representing 2 to 7% of such tumors. We explored the therapeutic efficacy of inhibiting ALK in such tumors in an early-phase clinical trial of crizotinib (PF-02341066), an orally available small-molecule inhibitor of the ALK tyrosine kinase.
Background. With the introduction of cisplatincontaining regimens in the treatment of advanced gastric cancer, promising clinical results have been reported. A 61.5% response rate was observed with a combination of 5‐fluorouracil (5‐FU) infusion and bolus cisplatin; however, the superiority of cisplatin‐containing regimens to other regimens has not been clearly verified in any randomized controlled studies. A prospective, randomized study of 5‐FU and cisplatin (FP) versus 5‐FU, doxorubicin, and mitomycin C (FAM) versus 5‐FU alone (FU) in previously untreated patients with advanced gastric cancer is reported.
Methods. A total of 324 patients were entered into the trial and 295 patients (103 for FP, 98 for FAM, 94 for FU) were evaluable. The patients were randomized to receive FP, FAM, or FU after stratifying by the following factors: performance status, presence of measurable disease, and resection of the primary tumor.
Results. The overall response rate for patients with measurable disease in the FP arm was significantly higher than in the FAM and FU arms (51% for FP; 25% for FAM; 26% for FU). The durations of response for each arm, however, were not significantly different. Even though the median time to progression for the FP arm (21.8 weeks) was longer than that for the FAM arm (12 weeks; P < 0.05) and for the FU arm (9.1 weeks; P < 0.005), there was no statistical difference in overall survival among the three arms. Toxicity for all three regimens was moderate and consisted primarily of myelosuppression, nausea, vomiting, and alopecia.
Conclusions. Although the FP regimen showed a significantly higher response rate and a longer time to progression than the FAM or FU regimens, a survival benefit was not observed.
Southern analysis showed that seven of nine human gastric cancer cell lines did not express DLC-1 mRNA, but contained the DLC-1 gene. To identify the mechanism of the loss of DLC-1 mRNA expression in these cell lines, we investigated the methylation status of DLC-1 gene by using methylation-specific PCR (MSP) and Southern blot, and found that five of seven DLC-1 nonexpressing gastric cancer cell lines were methylated in the DLC-1 CpG island. Treatment with 5-aza-2 0 -deoxycytidine (5-Aza-dC) induced DLC-1 mRNA expression in the gastric cancer cell lines that have the methylated alleles. Studies using SNU-601 cell line with methylated DLC-1 alleles revealed that nearly all CpG sites within DLC-1 CpG island were methylated, and that the in vitro methylation of the DLC-1 promoter region is enough to repress DLC-1 mRNA expression, regardless of the presence of transcription factors capable of inducing this gene. In all, 29 of 97 (30%) primary gastric cancers were also shown to be methylated, demonstrating that methylation of the DLC-1 CpG island is not uncommon in gastric cancer. In addition, we demonstrated that DLC-1 mRNA expression was induced, and an increase in the level of acetylated H3 and H4 was detected by the treatment with trichostatin A (TSA) in two DLC-1 nonexpressing cell lines that have the unmethylated alleles. Taken together, the results of our study suggest that the transcriptional silencing of DLC-1, by epigenetic mechanism, may be involved in gastric carcinogenesis.
We report 8 newly established gastric-carcinoma cell lines (SNU-216, 484, 520, 601, 620, 638, 668, 719) from Korean patients. Morphologic study was carried out using light and electron microscopes. CEA, aFP, and CA 19-9 and TPA in supernatant and in cell lysate were measured by radioimmunoassay. p53 and c-Ki-ras gene mutations were screened and confirmed by sequencing. The cell lines, derived from tumors with moderate differentiation, grew as a diffuse monolayer, and those from tumors with poor differentiation and minimal desmoplasia grew exclusively as non-adherent. Out of the 8 gastric-cancer cell lines, 5 had detectable levels of CEA both in supernatant and in cell lysate; there was no expression or secretion of aFP in these cells; 4 cell lines showed high levels of CA 19-9 in cell pellets. All cell lines except SNU-484 had high concentrations of TPA both in cell lysate and in supernatants. p53 mutation was found in 6 cell lines (75%): 2 (SNU-216 and SNU-668) had mutations in exon 6, and other 3 in exon 8. The c-Ki-ras mutation was found in 2 cell lines (25%), SNU-601 and SNU-668. The former showed GGT-to-GAT transition mutation at codon 12, while the latter showed CAA-to-AAA transversion mutation at codon 61. DNA profiles using restriction endonuclease HinfI and polymorphic DNA probes ChdTC-15 and ChdTC-114 showed different unique patterns; which suggests that these cell lines are unique and not cross-contaminated. We believe that the newly characterized gastric-cancer cell lines presented in this paper will provide a useful in vitro model for studies related to human gastric cancer. Int. J. Cancer, 70:0-0, 1997.r 1997 Wiley-Liss, Inc.
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