K H Lee

Thymidylate Synthase, Thymidine Phosphorylase, VEGF and p53 Protein Expression in Primary Colorectal Cancer for Predicting Response to 5-fluorouracil-based Chemotherapy

PURPOSE In the treatment of advanced metastatic colorectal cancer, several new agents, such as irinotecan and oxaliplatin, have been developed, which have improved both disease free and overall survivals. Among these agents, 5-fluorouracil (5-FU) still remains one of the most active agents, and the selection of patients who can benefit from 5-FU-based chemotherapy is still important, as those unlikely to benefit could be spared the harmful side effects. The expression levels of thymidylate synthase (TS), thymidine phosphorylase (TP) and p53 have been known to be associated with the clinical response to 5-FU-based therapy as well as the prognosis, and that of vascular endothelial growth factor (VEGF) is associated with poor survival. MATERIALS AND METHODS The relationship between the expressions of TS, TP, VEGF and p53 in primary tumors, using immunohistochemistry, and the response of 45 metastatic colorectal cancer patients (M:F=25:20, median age 59 yrs) to 5-FU-based chemotherapy were evaluated. RESULTS Thirty-seven patients were treated with 5-FU/LV/irinotecan (FOLFIRI) and 8 with 5-FU/LV/oxaplatin (FOLFOX). The overall response rate was 28.9% (13/45). When immunohistochemically analyzed with monoclonal antibodies against TS, TP, VEGF and p53, 55.6% of the patients (25/45) were positive for TS, 48.9% (22/45) for TP, 82.2% (37/45) for VEGF, and 80% (36/45) for p53. There was a significant difference in the intensity of TS expression between the clinical responders and non-responders (p=0.036). In terms of the staining pattern of TS expression, diffuse staining was correlated with a poor response (p=0.012) and poor survival (p=0.045). However, there was no correlation between the expressions of TP, VEGF or P53 and the response to chemotherapy. CONCLUSION These results suggest that the expression of TS in primary colorectal cancer might be an important prognostic factor for chemotherapy response and survival, and might be a useful therapeutic marker for the response of chemotherapy.

Influence of dietary avilamycin on ileal and cecal microbiota in broiler chickens

Abstract The mechanisms by which antibiotic growth promoters (AGP) enhance growth rates, feed efficiencies, and disease resistance in poultry need to be understood for designing safer and alternative strategies to replace AGP. Avilamycin has been widely used as an AGP in poultry, but its impact on the structure and function of the gut microbiome of broiler chickens has not been fully elucidated. In this study, we investigated the bacterial communities of the ileum and cecum in broiler chickens fed with an avilamycin‐supplemented diet, by high‐throughput sequencing of bacterial 16S rRNA genes. Alpha diversity metrics indicated that the ileal bacterial diversity was higher in avilamycin‐fed chickens than in the control group, whereas the opposite was true for the cecum. Multivariate analyses revealed that the ileal microbiota of the avilamycin‐fed group were clearly distinguished from those of the control group, whereas the cecal bacterial communities were apparently not influenced by feeding diets containing avilamycin. In the ilea, 2 operational taxonomic units (OTU) that matched Lactobacillus reuteri and Clostridium were enriched (P = 0.016 and P = 0.007, respectively) in the avilamycin‐fed group, and an OTU belonging to Lactobacillus crispatus was decreased (P = 0.016). In the cecal microbiota showing much higher diversity with 1,286 non‐singleton OTU, 12 OTU were decreased, and 3 were increased in response to avilamycin treatment (P = 0.005‐0.047). Functional profiling of bacterial communities based on PICRUSt analysis revealed that 10 functional categories were enriched by avilamycin treatments, and 4 functional categories were decreased. In conclusion, our results demonstrated that the influence of avilamycin supplementation on the diversity, taxonomic composition, and functional profiles of the microbiota was evidently different in the ileum and cecum. These results further our understanding of the impact of AGP on the composition and activity of commensal bacteria in the chicken gastrointestinal tract to develop novel feeding strategies for improving animal health and performance.