It has been shown that 1+ tumors often exhibit a greater frequency of TP53 mutations and an increased tumor mutational burden, resembling more of a basal phenotype, while 2+ tumors present a higher frequency of ERBB2 mutations, along with higher ERBB2 mRNA levels, resembling more of a HER2-enriched subtype [29]. This evidence concerns the gene TP53 and neoplasm.