Fig. 7: HLA-I expression and methylation in circulating tumor cells.

a Intra- and extracellular HLA-I protein expression in circulating tumor cells from two cohorts of 8 patients with prostate cancer. Dotted line represents median HLA-I expression in all patient matched white blood cells (WBCs). b Representative ×40 images of a CTC with low HLA-I expression and a WBC near the median expression from the total HLA-I group. Hoechst (Hst; blue; CD45/CD34/CD11b/CD27 (Excl; red); pan-cytokeratin (CK; white). Scale bars represent 10 µM. c Representative 10x images of HLA-I (yellow) undetectable and HLA-I detectable CTCs and a WBC (white arrow) in the single-cell aspirator microwells (Pt. 56) HLA-I (yellow), EpCAM (red), Excl. (white). Scale bars represent 10 µm. d Mean fluorescent intensity (MFI) of HLA-I in each CTC population and matched WBCs (where available). Statistical analysis was done by one-way ANOVA with the Kruskal–Wallis test, and Welch’s t-test for Pt 58. Approximately 10–15 CTCs were chosen to be aspirated from each group. e HLA-I methylation in 10 WBCs and 10 LNCaP cells purified by single-cell aspiration. f Relative LINE1 methylation in groups of ~10–15 CTCs purified by single-cell aspiration. g HLA-I methylation in HLA-I detectable and undetectable groups of ~10–15 CTCs purified by single-cell aspiration represented with a Methylation Index relative to methylation in LNCaP cells.