SYK and Hand-foot syndrome: The association of mRNA expression of SYK(T) and SYK(S) split into four quartiles (Q1 with lowest mRNA expression levels through Q4 with the highest mRNA expression levels) with HFS was visualized by Kaplan-Meier curves (Fig 3a and 3b), which suggested an impaired HFS particularly for patients with SYK(S) mRNA expression levels of the tumor in Q4.