No abstract

The present study aimed to clarify the incidence and clinical outcomes of nasopharyngeal carcinoma (NPC) in the Chubu region of Japan from 2006 to 2015, compared with previous reports. A retrospective analysis was conducted based on medical records from 40 hospitals located in the Chubu region in the central Japanese main island, with a population of around 22.66 million individuals. This study was designed in line with to two previous clinical studies into NPC conducted in the same area of Japan. We recruited NPC patients diagnosed in hospitals across this area over a 10-year period (2006–2015) using a questionnaire about sex, age, primary site, clinical symptoms, pathology, Union for International Cancer Control (UICC) staging, serological exam, treatment, and survival. A total of 620 NPC patients were identified. The age-standardized incidence of NPC from 2006 to 2015 was 0.27 per 100,000 individuals per year. There were no significant differences between this study and the previous two studies conducted in the same area of Japan. The five-year overall survival rate for all patients was 75.9%, while those for patients with stages I, II, III, and IVA were 97%, 91%, 79%, and 68%, respectively. The age-standardized annual incidence of NPC in the present study was 0.27 per 100,000 individuals per year, which was relatively low and stable. The five-year overall survival rate for all NPC patients was significantly improved in this decade compared with previous studies. The smoking rates in male and female NPC patients were 64.5% and 18.8%, respectively, thereby suggesting the involvement of smoking in the incidence of NPC.

Melanocytes are pigment-producing cells generated from neural crest cells (NCCs) that delaminate from the dorsal neural tube. The widely accepted premise that NCCs migrating along the dorsolateral pathway are the main source of melanocytes in the skin was recently challenged by the finding that Schwann cell precursors are the major cellular source of melanocytes in the skin. Still, in a wide variety of vertebrate embryos, melanocytes are exclusively derived from NCCs. In this study, we show that a NCC population that is not derived from Sox1 + dorsal neuroepithelial cells but are derived from Sox1 À cells differentiate into a significant population of melanocytes in the skin of mice. Later, these Sox1 À cells clearly segregate from cells that originated from Sox1 + dorsal neuroepithelial cell-derived NCCs. The possible derivation of Sox1 À cells from epidermal cells also strengthens their non-neuroepithelial origin.

Background: Neural crest cells (NC cells) are highly migratory multipotent cells. Their multipotency is transient at the early stage of their generation; soon after emerging from the neural tube, these cells turn into lineage-restricted precursors. However, recent studies have disputed this conventionally believed paradigm. In this study, we analyzed the differentiation potency of NC-derived cells after their arrival at target tissues. Results: Using Sox10-IRES-Venus mice, we found that the NC-derived cells in the skin, DRG, and inner ear could be divided into two populations: Sox10-positive/Kit-negative cells (Sox101/Kitcells) and Sox10-and Kit-positive cells (Sox101/Kit1 cells). Only the Sox101/Kit-cells were detected in the intestines. Unexpectedly, the Sox101/Kit1 cells differentiated into neurons, glial cells, and melanocytes, showing that they had maintained their multipotency even after having entered the target tissues. The Sox101/Kit1 cells in the DRG maintained their multipotency for a restricted period during the earlier embryonic stages, whereas those in the skin and inner ear were multipotent yet even in later embryonic stages. Conclusions: We showed that NC-derived Sox101/Kit1 cells maintained their multipotency even after entry into the target tissues. This unexpected differentiation potency of these cells in tissues seems to have been strictly restricted by the tissue microenvironment. Developmental Dynamics 243:368-380, 2014. V C 2013 Wiley Periodicals, Inc.Key words: neural crest; kit; Sox10; mouse Key findings:NC-derived cells in skin, DRG, and inner ear are divided into 2 populations: Sox101/Kit-cells and Sox101/ Kit1 cells. Sox101/Kit-cells in the skin and Sox101/Kit1 cells in DRGs and inner ear are previously unidentified NC-derived cells. The NC-derived Sox101/Kit1 cells maintain their multipotency even after having entered the target tissues. The differentiation potency of NC-derived cells in tissues is restricted depending on the tissue environment.

These results suggest that the decreased damping control by derivative gain for balance in the M/L direction is one of the risk factors for falls in the elderly.