For comparison, among 89 patients without molecular variants in none of NBN, MSH2 and RAD50 genes only three patients suffered from similar complications (enterocolitis grade 4, gastrointestinal bleeding grade 4 and central nervous system toxicity grade 4) despite an application of the same PPNG protocol (Additional file 2: Figure S1 A and B) and the difference was significant (p = 0.01). This evidence concerns the gene MSH2 and enterocolitis.