Fig. 4

Relationship between SPHK1 protein expression and cisplatin resistance in gastroesophageal cancer cell lines. a SPHK1 protein expression determined by semi-quantitative immunohistochemistry Q-score(see text) correlates with SPHK1 mRNA expression in drug resistant gastroesophageal cell lines(mean for all drug resistant cell lines and parental wild type lines, 3 independent replicates per cell line from three different passages measured by qRT-PCR (see also Additional file 1: Additional information 5). (R = 0.70, p = 0.022). b SPHK1 protein expression determined by semi-quantitative immunohistochemistry Q-score(see text) with IC50 for cisplatin in an independent panel of gastric cancer cell lines. (R = 0.532, p = 0.013)