We have isolated a novel liver-specific organic anion transporter, LST-1, that is expressed exclusively in the human, rat, and mouse liver. LST-1 is a new gene family located between the organic anion transporter family and prostaglandin transporter. LST-1 transports taurocholate (K _m = 13.6 μm) in a sodium-independent manner. LST-1 also shows broad substrate specificity. It transports conjugated steroids (dehydroepiandrosterone sulfate, estradiol-17β-glucuronide, and estrone-3-sulfate), eicosanoids (prostaglandin E₂, thromboxane B₂, leukotriene C₄, leukotriene E₄), and thyroid hormones (thyroxine,K _m = 3.0 μm and triiodothyronine,K _m = 2.7 μm), reflecting hepatic multispecificity. LST-1 is probably the most important transporter in human liver for clearance of bile acids and organic anions because hepatic levels of another organic anion transporter, OATP, is very low. This is also the first report of the human molecule that transports thyroid hormones.

The aim of the study was to evaluate the relationship between hospital volume and outcome after pancreaticoduodenectomy (PD). Previous reviews for the hospital volume-outcome relationship after pancreatic resection were limited owing to clinical or methodological heterogeneity, resulting from differences in surgical procedures and high-volume hospital (HVH) definitions across studies. We conducted a rigorous meta-analysis on the influence of hospital volume on various outcomes after PD using strict inclusion criteria and single cutoff values for HVHs. Thirteen studies based on nationwide databases from 11 countries, and including 58,023 patients in total, were included in this study. The overall pooled odds ratio (OR) for mortality favoring the HVH group was 2.37 [95% confidence interval (CI): 1.95-2.88] with high heterogeneity (I = 63%). We therefore classified all included studies into categories according to the cutoff values for HVH as defined in each individual study. The pooled OR for each category of 1 to 19, 20 to 29, and ≥30 PDs per year was 1.94, 2.34, and 4.05, respectively. There were significant differences among these categories (I = 58.9%, P = 0.09). The 2 former categories showed no statistical interstudy heterogeneities. The data did not suggest publication bias. These trends persisted in all subgroup analyses. Postoperative length of stay in the HVH group was significantly shorter with mild interstudy heterogeneity. This meta-analysis included studies from different countries with disparate health care systems and provided strong evidence for an inverse association between higher hospital volume and lower mortality after PD. Variations in HVH cutoff values across studies majorly influenced the overall heterogeneity.

5-Fluorouracil (5-FU) is a key anticancer drug that for its broad antitumor activity, as well as for its synergism with other anticancer drugs, has been used to treat various types of malignancies. In chemotherapeutic regimens, 5-FU has been combined with oxaliplatin, irinotecan and other drugs as a continuous intravenous infusion. Recent clinical chemotherapy studies have shown that several of the regimens with oral 5-FU drugs are not inferior compared to those involving continuous 5-FU infusion chemotherapy, and it is probable that in some regimens continuous 5-FU infusion can be replaced by oral 5-FU drugs. Historically, both the pharmaceutical industry and academia in Japan have been involved in the development of oral 5-FU drugs, and this review will focus on the current knowledge of 5-FU anabolism and catabolism, and the available information about the various orally-administrable 5-FU drugs, including UFT, S-1 and capecitabine. Clinical studies comparing the efficacy and adverse events of S-1 and capecitabine have been reported, and the accumulated results should be utilized to optimize the treatment of cancer patients. On the other hand, it is essential to elucidate the pharmacokinetic mechanism of each of the newly-developed drugs, to correctly select the drugs for each patient in the clinical setting, and to further develop optimized drug derivatives.

Certain genetic alterations and right-sided primary tumor location are associated with resistance to anti-epidermal growth factor (EGFR) treatment in metastatic colorectal cancer (mCRC). The phase 3 PARADIGM trial (n = 802) demonstrated longer overall survival with first-line anti-EGFR (panitumumab) versus antivascular endothelial growth factor (bevacizumab) plus modified FOLFOX6 in patients with RAS wild-type mCRC with left-sided primary tumors. This prespecified exploratory biomarker analysis of PARADIGM (n = 733) evaluated the association between circulating tumor DNA (ctDNA) gene alterations and efficacy outcomes, focusing on a broad panel of gene alterations associated with resistance to EGFR inhibition, including KRAS, NRAS,PTEN and extracellular domain EGFR mutations, HER2 and MET amplifications, and ALK, RET and NTRK1 fusions. Overall survival was prolonged with panitumumab plus modified FOLFOX6 versus bevacizumab plus modified FOLFOX6 in patients with ctDNA that lacked gene alterations in the panel (that is, negative hyperselected; median in the overall population: 40.7 versus 34.4 months; hazard ratio, 0.76; 95% confidence interval, 0.62–0.92) but was similar or inferior with panitumumab in patients with ctDNA that contained any gene alteration in the panel (19.2 versus 22.2 months; hazard ratio, 1.13; 95% confidence interval, 0.83–1.53), regardless of tumor sidedness. Negative hyperselection using ctDNA may guide optimal treatment selection in patients with mCRC. ClinicalTrials.gov registrations: NCT02394834 and NCT02394795.

Recent studies have shown that the tumor microenvironment plays a significant role in the progression of solid tumors. As an abundant component of the tumor microenvironment, cancer‐associated fibroblasts (CAFs) have been shown to promote tumorigenesis and cancer aggressiveness, but their molecular characteristics remain poorly understood. In the present study, paired CAFs and normal fibroblasts (NFs) were isolated from five colorectal cancer (CRC) tissues from patients who underwent surgical resection. The gene expression profiles of CAFs and NFs identified by RNA sequencing were compared to understand the complex role of CAFs in cancer progression. Gene Set Enrichment Analysis revealed that the gene sets related to the Wnt signaling pathway were highly enriched in CAFs, as well as TGFβ signaling, which is considered to be a regulator of CAFs. Among the components of this pathway, Wnt2 was specifically expressed. The observations led us to speculate that Wnt2 is extremely involved in regulating CRC progression by CAFs. Thus, we performed immunohistochemical analysis on Wnt2 in 171 patients who underwent surgery for colorectal adenocarcinoma. Positive staining for Wnt2 was mainly observed in cancer stroma, although the immunoreactivity was weak in cancer cells. Wnt2 expression in CAFs was significantly correlated with depth of tumor (P < .001), lymph node metastasis (P = .044), TNM stage (P = .010), venous invasion (P < .001), and recurrence (P = .013). Subsequent in vitro analyses were conducted using conditioned medium (CM) from immortalized CAFs transfected with siRNA targeting Wnt2. As a result, cancer cell invasion and migration were significantly decreased in the CM from immortalized CAFs transfected with siRNA targeting Wnt2. Our findings indicated that Wnt2 protein released from CAFs enhances CRC cell invasion and migration. In conclusion, Wnt2 secreted by CAFs plays a key role in cancer progression and is a potential therapeutic target for CRC.