LOH analysis at 17p13.3 in B-PLL cases. Genomic DNA from the samples studied were digested with Pst I, subjected to Southern blot, and probed with the clone p144-D6. Cases were scored positive for LOH when displaying only one allelic band with both probes. Nine of the B-PLL cases show only one band with p144-D6. However, in case no. 8, two bands were observed with pYNZ22 probe. Lane 0, control DNA from a normal sample.