Noriaki Otagiri

Detailed deletion mapping of chromosome band 14q32 in human neuroblastoma defines a 1.1-Mb region of common allelic loss

Neuroblastoma (NB) is a well-known malignant disease in infants, but its molecular mechanisms have not yet been fully elucidated. To investigate the genetic contribution of abnormalities on the long arm of chromosome 14 (14q) in NB, we analysed loss of heterozygosity (LOH) in 54 primary NB samples using 12 microsatellite markers on 14q32. Seventeen (31%) of 54 tumours showed LOH at one or more of the markers analysed, and the smallest common region of allelic loss was identified between D14S62 and D14S987. This region was estimated to be 1-cM long from the linkage map. Fluorescence in situ hybridization also confirmed the loss. There was no statistical correlation between LOH and any clinicopathologic features, including age, stage, amplification of MYCN and ploidy. We further constructed a contig spanning the lost region using bacterial artificial chromosome and estimated this region to be approximately 1.1-Mb by pulsed-field gel electrophoresis. Our results will contribute to cloning and characterizing the putative tumour-associated gene(s) in 14q32 in NB.

The surgical and oncological outcomes of conversion surgery for patients with initially unresectable gastric cancer

Background: Conversion therapy is a surgical option for unresectable gastric cancer in cases wherein non-curative factors are initially managed by induction chemotherapy. However, the indications for resection remain unclear. Thus, this study aimed to assess the feasibility and efficacy of conversion therapy, based on the data from our facility. Methods: Patients (n=97) with unresectable gastric cancer received chemotherapy in our facility between January 2010 and August 2016. Surgical resection was performed in 16 of them after chemotherapy had rendered the tumor resectable. We retrospectively examined clinicopathological variables and oncologic outcomes in these 16 cases. Results: Of the 16 patients who underwent resection, R0 resection was possible in 15 patients, whereas R1 resection was performed in the remaining 1 patient. Postoperative complications arose in 6 patients (37.5%) but with no mortality. The median overall survival (OS) in the conversion therapy patients (n=16) was 50 months. Among the patients who underwent conversion therapy, univariate analysis showed that the patients with type 4 gastric cancer had a poor prognosis (P=0.0009). Conclusion: The conversion therapy may improve OS in only some of the patients who responded to induction chemotherapy, our results suggest that conversion therapy does not improve the outcomes in patients with type 4 gastric cancer.