Naoki Iwata

The prognosis of colorectal cancer is closely linked to the occurrence of distant metastases. Systemic dissemination is most likely caused by circulating tumor cells (CTC). Despite the fundamental role of CTC within the metastatic cascade, technical obstacles have so far prevented detailed genomic and, in particular, phenotypic analyses of CTC, which may provide molecular targets to delay or prevent distant metastases. We show here a detailed genomic analysis of single colorectal cancer-derived CTC by array comparative genomic hybridization (aCGH), mutational profiling, and microsatellite instability (MSI) analysis. Furthermore, we report the first gene expression analysis of manually selected colorectal cancer-derived CTC by quantitative real-time PCR (qRT-PCR) to investigate transcriptional changes, enabling CTC to survive in circulation and form distant metastases. aCGH confirmed the tumor cell identity of CellSearch-isolated colorectal cancer-derived CTC. Mutational and MSI analyses revealed mutational profiles of CTC to be similar, but not identical to the corresponding tumor tissue. Several CTC exhibited mutations in key genes such as KRAS or TP53 that could not be detected in the tumor. Gene expression analyses revealed both a pronounced upregulation of CD47 as a potential immune-escape mechanism and a significant downregulation of several other pathways, suggesting a dormant state of viable CTC. Our results suggest mutational heterogeneity between tumor tissue and CTC that should be considered in future trials on targeted therapy and monitoring of response. The finding of upregulated immune-escape pathways, which may be responsible for survival of CTC in circulation, could provide a promising target to disrupt the metastatic cascade in colorectal cancer. Cancer Res; 74(6); 1694-704. ©2014 AACR.

Evidence indicates that impaired immunocompetence and nutritional status adversely affect short-term and long-term outcomes of patients with cancer. We aimed to evaluate the clinical significance of preoperative immunocompetence and nutritional status according to Onodera's prognostic nutrition index (PNI) among patients who underwent curative gastrectomy for gastric cancer (GC).This study included 260 patients with stage II/III GC who underwent R0 resection. The predictive values of preoperative nutritional status for postoperative outcome (morbidity and prognosis) were evaluated. Onodera's PNI was calculated as follows: 10 × serum albumin (g/dL) + 0.005 × lymphocyte count (per mm).The mean preoperative PNI was 47.8. The area under the curve for predicting complications was greater for PNI compared with the serum albumin concentration or lymphocyte count. Multivariate analysis identified preoperative PNI < 47 as an independent predictor of postoperative morbidity. Moreover, patients in the PNI < 47 group experienced significantly shorter overall and disease-free survival compared with those in the PNI ≥ 47 group, notably because of a higher prevalence of hematogenous metastasis as the initial recurrence. Subgroup analysis according to disease stage and postoperative adjuvant treatment revealed that the prognostic significance of PNI was more apparent in patients with stage II GC and in those who received adjuvant chemotherapy.Preoperative PNI is easy and inexpensive to determine, and our findings indicate that PNI served as a significant predictor of postoperative morbidity, prognosis, and recurrence patterns of patients with stage II/III GC.

OBJECTIVE: To develop novel diagnostic and therapeutic targets specific for peritoneal metastasis of gastric cancer (GC). BACKGROUND: Advanced GC frequently recurs because of undetected micrometastases even after curative resection. Peritoneal metastasis has been the most frequent recurrent pattern after gastrectomy and is incurable. METHODS: We conducted a recurrence pattern-specific transcriptome analysis in an independent cohort of 16 patients with stage III GC who underwent curative gastrectomy and adjuvant S-1 for screening candidate molecules specific for peritoneal metastasis of GC. Next, another 340 patients were allocated to discovery and validation sets (1:2) to evaluate the diagnostic and predictive value of the candidate molecule. The results of quantitative reverse-transcription PCR and immunohistochemical analysis were correlated with clinical characteristics and survival. The effects of siRNA-mediated knockdown on phenotype and fluorouracil sensitivity of GC cells were evaluated in vitro, and the therapeutic effects of siRNAs were evaluated using a mouse xenograft model. RESULTS: Synaptotagmin VIII (SYT8) was identified as a candidate biomarker specific to peritoneal metastasis. In the discovery set, the optimal cut-off of SYT8 expression was established as 0.005. Expression levels of SYT8 mRNA in GC tissues were elevated in the validation set comprising patients with peritoneal recurrence or metastasis. SYT8 levels above the cut-off value were significantly and specifically associated with peritoneal metastasis, and served as an independent prognostic marker for peritoneal recurrence-free survival of patients with stage II/III GC. The survival difference between patients with SYT8 levels above and below the cut-off was associated with patients who received adjuvant chemotherapy. Inhibition of SYT8 expression by GC cells correlated with decreased invasion, migration, and fluorouracil resistance. Intraperitoneal administration of SYT8-siRNA inhibited the growth of peritoneal nodules and prolonged survival of mice engrafted with GC cells. CONCLUSIONS: SYT8 represents a promising target for the detection, prediction, and treatment of peritoneal metastasis of GC.

A variety of systemic inflammation-based prognostic scores have been explored; however, there has been no study to clarify which score could best reflect survival in resected pancreatic cancer patients.Between 2002 and 2014, 379 consecutive patients who underwent curative resection of pancreatic cancer were enrolled. The Glasgow Prognostic Score (GPS), modified GPS (mGPS), neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), prognostic index (PI), and prognostic nutritional index (PNI) scores for each patient were calculated. Survival of each score was evaluated, and correlations between the score selected on the basis of the prognostic significance and various clinicopathological factors were analyzed.In the analysis of the GPS, the median survival time (MST) was 28.1 months for score 0, 25.6 for score 1, and 17.0 for score 2. As for mGPS, the MST was 25.8 months for score 0, 27.7 for score 1, and 17.0 for score 2. Both scores were found to be significant. On the contrary, there were no statistical differences in MST between various scores obtained using the NLR, PLR, PI, or PNI. Multivariate analysis revealed that lymph node metastasis, positive peritoneal washing cytology, and a GPS score of 2 were significant prognostic factors. There was also statistically significant correlation between the GPS score and tumor location (head), tumor size (≥2.0 cm), bile duct invasion, and duodenal invasion.Our study demonstrated that the GPS could be an independent predictive marker and was superior to other inflammation-based prognostic scores in patients with resected pancreatic cancer.