Fig. 1.

Favorable survival of ALDH1A2^high OPSCC depends on the presence of CRABP2. a Representative pictures of IHC stained tissue sections demonstrate heterogeneous expression (brown signal) of key regulators of RA signaling in keratinocytes of normal mucosa (left panel) and tumor cells of primary OPSCC (middle and right panel). Counterstaining with hematoxylin to visualize tissue architecture; white bar = 200 μm. b Association between subgroups with ALDH1A2^highCRABP2^high (blue line), ALDH1A2^highCRABP2^low (red line) and ALDH1A2^low (green line) staining pattern and overall survival was assessed by univariate Kaplan-Meier analysis. Number at risk indicates the total amount of patients per subgroup, which were alive and not censored at the indicated time points and were considered to calculate the overall survival probability. P values were calculated by log-rank test