Both mouse and zebrafish homozygous ESCO2 null animals are embryonic lethal[44, 45], therefore to determine if reduction in ESCO2 specifically contributes to tumorigenesis, we generated and monitored tumor formation in cohorts (N = 96/cohort) of esco2+/+ and esco2hi2865/+ (hi2865 allele is an intron 1 gene trap that results in >95% knockdown of transcript) zebrafish in a tumor sensitized p53 mutant background, p53zy7/+ (zy7 allele is a thymine to cytosine transition in codon 164 in the p53 DNA binding domain that results in the inability of DNA binding)[22, 44]. This evidence concerns the gene ESCO2 and neoplasm.