MET dysregulation is a hallmark of aggressive disease in multiple myeloma patients.

Abnormal activation of MET/ HGF ( Hepatocyte Growth Factor) pathway has been described in several tumours and increased HGF plasmatic levels have been detected in patients with aggressive multiple myeloma (MM). MET and HGF m RNA expression was investigated in 105 samples of purified plasma cells derived from newly diagnosed MM patients treated with bortezomib-based induction therapy. Gene expression was compared with response to therapy and clinical outcome. MET gene copy number was also evaluated. MET m RNA expression was higher in CD138+ than in CD138− cells (median 76·90 vs. 11·24; P = 0·0009). Low MET m RNA expression characterized patients with better response (complete response or very good partial response) compared to other patients (median 56·10 vs. 134·83; P = 0·0006). After a median follow-up of 50 months, patients with high MET m RNA expression displayed a worse progression-free survival ( PFS; P = 0·0029) and overall survival ( OS; P = 0·0023) compared to those with low MET m RNA levels. Patients with both high MET m RNA expression and high β2-microglobulin level (>5·5 mg/l) had further worse median PFS ( P < 0·0001) and OS ( P < 0·0001). Patients carrying 4 MET gene copies (8 out of 82, 9·8%) also had a short PFS. High MET m RNA expression identifies patients with dismal PFS and OS and the combination with high β2-microglobulin further characterizes patients with worse outcome. [ABSTRACT FROM AUTHOR]