No abstract

SATB2 (Special AT-rich sequence-binding protein 2) has recently been shown to be a specific biomarker of colorectal cancer (CRC). The aim of this study was to investigate the diagnostic potential of SATB2 as a means of detecting a CRC origin for liver metastases. SATB2 expression was examined in a resection cohort of 101 CRC and 273 non-CRC adenocarcinoma samples using immunohistochemistry (IHC). The diagnostic accuracy of CRC origins of liver metastases based on SATB2 and a three marker panel of SATB2, CK20 and CDX2 was evaluated using an independent cohort of 192 liver biopsies. IHC showed 97 of the 101 (96.0%) primary CRC samples were SATB2 positive, compared to only 6 of the 273 (2.1%) samples of other cancer types. The sensitivity, specificity and AUC values of SATB2 expression in resection samples were 97%, 97.1% and 0.977, respectively. Meanwhile, for the liver biopsy samples, the sensitivity, specificity and AUC values of a CRC liver metastases was 92.2%, 97.8% and 0.948 for SATB2, 95.1%, 91.0% and 0.959 for CK20, and 100%, 85.4% and 0.976 for CDX2, respectively. Further analysis demonstrated that all three-marker positivity was detected in 92/103 (89.3%) CRC and 2/89 (2.2%) non-CRC liver metastases sampled by biopsy. Our findings suggest that SATB2, as measured by IHC, could serve as a promising diagnostic biomarker of CRC metastases. Combining evaluation of SATB2 with CK20 and CDX2 to form a three marker panel further improved the detection of metastatic CRCs in liver biopsy tissues.

No abstract

Nitrate (NO3−), one of the most important inorganic aerosols in the atmosphere, is mainly formed by oxidation of NOx by the hydroxyl radical (OH) and ozone (O3) in urban atmospheres. However, the fractional contributions of its various oxidation pathways remain unclear. Here, we collected particulate matter with aerodynamic diameter less than 2.5 μm (PM2.5) samples in a second‐tier city in southeast China from 1 September to 31 December 2017 and measured the NO3− and nitrate isotopic compositions (δ15N and δ18O). The average concentration of NO3−, δ15N, and δ18O values were 14.7 ± 11.6 μg/m3, (+4.3 ± 4.3)‰, and (+71.8 ± 14.7)‰ with the ranges from 0.8 to 57.7 μg/m3, −10.5‰ to +12.5‰ and +34.5‰ to +91.9‰, respectively. All three species were significantly higher in winter than in summer. Based on a Bayesian mixing model with a dual isotope array for NO3−, contributions of (37.1 ± 33.4)%, (60.3 ± 32.2)%, and (2.6 ± 2.7)% to NO3− could be attributed to OH oxidation, N2O5 hydrolysis, and NO3 + hydrocarbon (HC) pathways, respectively. Higher OH radical concentrations with higher ratios of OH to O3 led to lower NO3− concentrations, while lower OH radical concentrations with higher ratios of O3 to OH led to higher contributions of N2O5 hydrolysis, forming higher NO3− concentrations in winter. Under low OH, an increased O3 to NOx ratio increased the contribution of the NO3 + HC pathway. The comprehensive analysis of the isotopic compositions of nitrate helped identify the importance of major oxidation pathways of NOx in this city.