Validation of urinary 1,2-dichloropropane concentration as a biological exposure index for workers exposed to 1,2-dichloropropane.

BACKGROUND: The International Agency for Research on Cancer classified 1,2-dichloropropane (1,2-DCP) as a human carcinogen in 2016. It is necessary to establish a health monitoring system for workers exposed to 1,2-DCP. We investigated the correlation between 1,2-DCP concentration in air and urine to determine whether it is appropriate to measure 1,2-DCP in urine as a biological exposure index (BEI). METHODS: Twenty-seven workers from 3 manufacturing industries handling 1,2-DCP participated in this study. Airborne 1,2-DCP was collected by personal air. Urine samples were collected at the end of work and analyzed using gas chromatography-mass spectrometry. Correlation analysis and simple regression analysis were performed to investigate the relationship between 1,2-DCP concentration in urine and air. RESULTS: Pearson correlation coefficients between total 1,2-DCP in air and urine (uncorrected, creatinine-corrected) were 0.720 and 0.819, respectively. For urine samples analyzed within 2 weeks, the Spearman's rho of 1,2-DCP concentration in urine (uncorrected and creatinine-corrected) was 0.906 and 0.836, respectively. Simple regression analysis of 1,2-DCP in air and urinary 1,2-DCP concentrations within 2 weeks, which showed the highest correlation, revealed that the coefficient of determination of 1,2-DCP concentration in urine (uncorrected and creatinine-corrected) was 0.801 and 0.784, respectively. CONCLUSIONS: As a BEI for workers exposed to 1,2-DCP, urinary 1,2-DCP without creatinine correction better reflects the exposure levels of 1,2-DCP in air.

Risk factors including night shift work of colorectal polyp.

BACKGROUND: The destruction of circadian rhythms by night shift work affects major circadian genes, which are known to play a role in advancing or killing the cell cycle through tumor suppressor genes. To find out whether night shift work affects the incidence of colorectal cancer, which was found to be associated with long-term night shift work in previous studies, we surveyed effect of night shift work on colorectal polyps that have a higher incidence than colorectal cancer and can progress to colorectal cancer. METHODS: To examine the correlation between rotating night shifts and colorectal polyps, a survey was conducted with 299 men aged 40-60 years from two university hospitals. We examined lifestyle, work history, work patterns, and colonoscopy results. The differences in prevalence among the groups was compared, and prevalence ratio (PR) was calculated via generalized linear modeling. RESULTS: The prevalence of colorectal polyps in night shift and non-shift workers were 53.0% and 33.5%, respectively. After adjusting for age, smoking status, dietary habits, family history of colorectal cancer, obesity, job type, night shift work (PR: 1.13, 95% CI: 1.02-1.25) was a risk factor of colorectal polyps. CONCLUSIONS: The risk of colorectal polyps was greater in night shift workers than non-shift workers. Also risk of colorectal polyp was higher in older group. Our study investigated colorectal polyp instead of colorectal cancer and lacks information about types and gene mutations of colorectal polyps. Further study is needed to clarify effect of night shift work on development of colorectal cancer.

Over-expression of miR-145 enhances the effectiveness of HSVtk gene therapy for malignant glioma.

This study attempts to combine two findings toward developing a rational strategy for improved therapy for glioma. One of the findings, made in this pre-clinical study, is that an hTERT-targeting ribozyme-controlled HSVtk gene (hTERT.Rz.HSVtk) exerts anti-tumor effects. The second observation is that the over-expression of a small noncoding RNA, miR-145, causes down-regulation of metastasis-related genes, such as PLAUR, SPOCK3, ADAM22, SLC7A5 and FASCN1. While blocking in vivo tumor growth only slightly, over-expression of miR-145 significantly inhibits both the migration and invasion of U87MG/U373MG glioma cells. We hypothesized that a simultaneous adenoviral-mediated over-expression of miR-145 might enhance the anti-tumor effects of hTERT.Rz.HSVtk and that a combination therapy with miR-145 and the HSVtk gene would be an effective approach for treating glioma. We tested this by developing adenoviral vectors that over-express miR-145 under the CMV promoter and employing them in combination with hTERT.Rz.HSVtk expression, both in vitro and in vivo in animal studies. We found that the adenovirus Ad5CMV.Rz.HSVtk.miR145 harboring an HSVtk expression cassette plus miR-145 produced prolonged survival benefits compared to administration of Ad5CMV.Rz.HSVtk or Ad5CMV.miR-145 alone. This study demonstrates that combination therapy using the hTERT.Rz.HSVtk gene together with miR-145 over-expression produces enhanced anti-tumor effects compared to that resulting from hTERT.Rz.HSVtk gene therapy alone.

The role of postoperative external-beam radiotherapy in the management of patients with papillary thyroid cancer invading the trachea.

PURPOSE: To determine the role of adjuvant external-beam radiotherapy (EBRT) in the management of patients with well-differentiated thyroid cancer invading the trachea. METHODS AND MATERIALS: Of 1,098 thyroid cancer patients, 68 (6%) were found to have tracheal invasion, and they all received "shave" excision of the tracheal cartilage. Among them, 12 patients had no postoperative residuum, 43 patients had microscopic residuum, and 13 patients had macroscopic residuum. All patients were divided into two groups according to treatment modality with or without EBRT; (1) the control group (n = 43) and (2) the EBRT group (n = 25). RESULTS: The locoregional recurrence rate for EBRT patients was much lower than that of control patients (51% for the control group vs. 8% for the EBRT group) (p < 0.01). The 10-year local progression-free survival rate for the EBRT group was significantly better than that of the control group (89% in the EBRT group vs. 38% in the control group) (log-rank, p < 0.01). The use of adjuvant EBRT after conservative surgery was an independent prognostic factor in univariate and multivariate analyses. CONCLUSIONS: External-beam radiotherapy was found to be effective, particularly in patients with thyroid cancer invading the trachea with microscopic or gross residuum after conservative surgery.