RT-PCR analysis of MAL expression in PMBLs and peripheral DLBLs. One microgram of RNA extracted from 12 PMBLs and 8 peripheral DLBLs was reverse transcribed and the cDNAs were coamplified with MAL and S14 primers. PCR products were run on a 2% agarose gel stained with ethidium bromide. Specific amplification of MAL and S14 cDNAs produced 520- and 141-bp bands, respectively. Positive control represented by serial dilutions of Jurkat cDNA and a negative control without template (T−) are included.