(A) Gene expression analysis was conducted using public data sets obtained from GEO site at the NCBI (http://www.ncbi.nlm.nih.gov/geo/). The data processed as quantile normalized intensity value. Significances were analyzed by Mann-Whitney U test, and the positive correlation coefficient (r) was calculated by Pearson correlation test for healthy controls (n = 24) and NASH patients (n = 19); *P < 0.05. (B) Immunohistochemistry staining of 12-LOX in the liver specimens of the Biomax human tissue array is shown. The 12-LOX positive area was analyzed by Image J. *P < 0.05 (n = 10 for healthy controls; n = 7 for chronic hepatitis without B virus). Scale bar: 15 μm. For quantification, 8 fields of each specimen were analyzed. (C) Expression of 12-LOX and CD68 was visualized by red and green immunofluorescence in the liver specimens of the Biomax human tissue array. The nuclei were stained by DAPI that indicate nuclei of all the parenchymal and nonparenchymal liver cells. Colocalization of 12-LOX and CD68 were assessed by yellow colored dots that counted from at least 5 images per tissue using Image J software (n = 17 for healthy controls; n = 15 for chronic hepatitis without B virus). **P < 0.01. Scale bar: 40 μm. (D) THP-1 cells were treated with 200 nM MaR1 or 5 μM SR1078 for 24 hours. The mRNA levels of RORA, ALOX12, and ALOX15 were analyzed by qRT-PCR. *P < 0.05 (n = 3). The data represent mean ± SD. Data were analyzed by Mann–Whitney U test for simple comparisons. (E) Schematic model for the mechanism of MaR1/RORα/12-LOX autoregulatory circuit for M2 polarity switch in the liver macrophages.