Fig 1: Patient tumor sample data (UNC337) indicate that CYP1B1 is associated with poor prognosis and reduced CLDN7 expression. (A–F) Data from breast cancer samples were grouped into the five intrinsic subtypes: basal-like (BL), claudin-low (CL), human epidermal growth factor receptor (HER2+), luminal A (LumA), and luminal B (LumB); UNC337 patient tumor sample database [5]. (A,B) Patient tumor sample data were separated into tertiles (104 high, 103 middle, and 103 low) of CYP1B1 RNA levels. (A) Survival probability was calculated using Kaplan-Meier analysis. Tumor patients with high CYP1B1 RNA levels had decreased probability of survival (Mantel-Cox test; p = 0.0115). (B) Disease-free survival was calculated using Kaplan-Meier analysis. Tumor patients with high CYP1B1 RNA levels have decreased probability of disease-free survival (Mantel-Cox test; p = 0.0111). (C,D) All 331 sample gene expression is shown as log2 (fold-change) relative to the mean expression of all samples. (C) Mean CYP1B1 RNA levels are elevated in CL tumor samples in comparison to all other samples. Boxplots show the inter-quartile range (IQR) within the box. The IQR is 25th percentile (Quartile 1) to 75th percentile (Quartile 3). The notch shows the 95% confidence interval of the median, and the whiskers include values within ±1.5 IQR and 99.3% of the data points. Two-sample t-test (p = 0.05) of the means were corrected for multiple comparisons using Bonferroni’s correction. (D) CYP1B1 RNA levels predict CLDN7 RNA levels The coefficient of the linear regression line, Beta one hat (ß^1), is the estimate of the slope of the line that best fits the data points. The significance of this value was determined by t-test. (E) Combined BL and CL tumor samples contain more CYP1B1HI/CLDN7LOW samples than combined (LumA+ B+ HER2+) samples. Samples with >10% increase in CYP1B1 RNA levels and >10% decrease in CLDN7 RNA levels were classified as CYP1B1HI/CLDN7LOW relative to RNA levels in all other samples. Sixty-one percent of CYP1B1HI/CLDN7LOW samples were subtyped as CL or BL, while only 27% of all other samples were CL or BL. (F) Patients with CYP1B1HI/CLDN7LOW have decreased overall survival and disease-free survival. Red lines and whiskers show the median ± IQR. The * indicates a significant difference (p = 0.05) from comparison of CYP1B1HI/CLDN7LOW to all other samples by the Mann-Whitney test.