Restoration of miR-34 by MIF lentiviral system inhibits Kato III tumorspheres. Kato III cells infected by miR-34a MIF or control vector MIF were plated for tumorsphere formation as described in Materials and Methods. 7–10 days later, tumorspheres were observed under microscope (A) and quantified (B). C. Quantification of cell numbers per tumorsphere. Tumorspheres were collected and filtered through a 40 um sieve (BD Biosciences), and dissociated with trypsin for single cell suspension. Cells were counted with trypan blue exclusion and the data are presented as number of cells per tumorsphere. **P < 0.01, Student's t-test, n = 3.