In the mutated cases, the mutation frequency ranged from 2.1 11.7%.
In these studies KRAS exon 3 mutation frequency ranged between 3.7% and 6.5% (weighted average 4.1%), while that of KRAS exon 4 mutations ranged between 3.3% and 6.5% (weighted average 4.9%).
This extensive meta-analysis, however, involved 2 Japanese studies with 103 CRC patients, corresponding to only 2.9% of all cases evaluated, and the TP53 mutation frequency ranged widely from 31%to84%4%.
Since 2005, the impact of PIK3CA mutations on MCRC patients treated with anti-EGFR has been investigated by several studies that have reported a PIK3CA mutation frequency ranging from 6 to 13% (Moroni et al, 2005; Lièvre et al, 2006; Perrone et al, 2009; Prenen et al, 2009; Sartore-Bianchi et al, 2009).
Although nucleotide misincorporation was not found in vivo, the frequency of single-nucleotide deletion was observed to be sequence-dependent, with mutation frequencies ranging from 1 to 26%.
This is in agreement with the literature in which KRAS mutation frequencies range from 30 to 50% (Jimeno et al, 2009; Peeters et al, 2009).
These same studies found BRAF mutation frequencies ranging from 48.6% to 76.1% in MSI-high CRCs (Table 3) [ 20, 36, 37].
Diploid species such as barley, sorghum, pea, peanut, and rice have low mutation frequencies ranging from 1/300 to 1,000 kb compared to the polyploids such as oat, bread wheat, and soybean [ 5, 6, 10, 11, 15, 16].
In contrast to γ-OH-PdG, the permanently ring-closed PdG adduct caused comparable mutation frequencies (ranging from ∼6 to 8%), regardless of whether single- or double-stranded vectors were utilized.
Importantly, our use of quantitative pyrosequencing analysis allowed us to identify mutations in K-Ras, B-Raf and PIK3CA with mutation frequencies ranging from 10 to 30%, which were not detected by automatic base calling software, routinely used in the analysis of dideoxy sequencing traces.
For example, Malone and colleagues [ 44] provide a summary of the literature and report that in women with extensive family histories, estimates of mutation frequency range from 20%to50%0%.
