Detection of β2 laminin mRNA by RT-PCR. mRNA was obtained from MACS-purified normal CD34⁺ peripheral blood progenitor cells and an oral squamous cell carcinoma cell line (positive control). RT-PCR (40 cycles) of the laminin β2 chain subunit mRNA resulted in a 315-bp fragment. Lane 1, 20-bp ladder; lane 2, CD34⁺ cells; lane 3, oral squamous cell carcionoma cell line; lane 4, control (primers only).