Table 3.

Features of mutations in the BCL-6 5′-noncoding region and IgV_H genes of normal GC cells vs. DLCL

	BCL-6		IgVH
	Normal GC	DLCL	Normal GC	DLCL
Frequency × 10−2/bp (range)	0.05 (0-0.4)	0.23 (0-1.6)*	5 (0-13)	15.2 (6.3-20.5)
Single bp substitutions	66	53	323	187
Deletions	2	3	2	0
Transitions/transversions†	1.2	1.2	1.4	1.2
Strand polarity†‡	1	1.1	1.9	1.5
RGYW bias§	0.21 (<0.05)	1.2 (<0.05)	21.3 (<0.001)	53 (<0.001)

^*The overall frequency of BCL-6 mutations in DLCL is extrapolated from the frequency of mutated cases occurring in this group (60%). 

^†The frequency of substitutions affecting each base was corrected for the base composition of the region analyzed. 

^‡Values designate the ratio of A → N vs. T → N substitutions. 

^§Normalized frequency of mutated G bases occurring in the context of an RGYW motif (see text). In parenthesis, the statistical significance compared with the expected frequency of mutations is shown, as calculated by the χ² test.