Increased cytoplasmic level of migfilin is associated with higher grades of human leiomyosarcoma

Aims: Leiomyosarcomas (LMS) are malignant neoplasms composed of cells that exhibit distinct smooth muscle differentiation. The molecular and cytogenetic features of LMS are complex and no consistent aberrations have been reported to date. Mitogen inducible gene‐2 (Mig‐2), kindlin and migfilin are recently identified cell–matrix adhesion proteins. The aim was to determine the expression and distribution of these proteins in human smooth muscle tumours of somatic soft tissue. Methods and results: Immunohistochemistry was performed on a human LMS tissue microarray and on sections of human leiomyomas (LM) and normal smooth muscle. Migfilin was barely detectable in normal smooth muscle cells, whereas increased levels of migfilin were observed in the majority of LM and LMS. Furthermore, the cytoplasmic level of migfilin was strongly associated with higher tumour grades. Additionally, the cytoplasmic levels of migfilin and Mig‐2 were correlated with each other, suggesting an association between the two in the cytoplasm. Kindlin was expressed in normal smooth muscle, LM and LMS, and its level did not correlate with tumour grade. Conclusions: Our results suggest a role for cytoplasmic migfilin in the progression of LMS and identify cytoplasmic migfilin as a potentially important biological marker for human LMS progression.