Fig. 2.

a Box plot analysis of IL-15 expression in the sera of patients with lymph node metastasis who died in the follow-up period, demonstrate considerably increased IL-15 values in contrast to the notable low IL-15 levels in patients with lymph node metastasis who were living up to follow-up (p = 0.001). b Box plot analysis showing the collective of patients with no lymph node involvement (N0) that died during the follow-up period. This group demonstrate significantly higher levels of IL-15 in contrast to the significantly decreased IL-15 levels in patients who remained alive (p = 0.014). The range amongst the 25th and 75th percentiles is demonstrated by boxes with a horizontal line at the median. The bars display the 5th and 95th percentiles. Circles specify values more than 1.5 box lengths. Asterisks specify values (marked with a number) more than 3.0 box lengths from the 75th percentile. Receiver operator curve analysis of sensitivity versus specificity gave an area under the curve (AUC) of 0.697 (a) and 0.755 (b), respectively