Algorithm for the diagnosis of STIC. Foci showing a Ki-67 labeling index >10% are considered Ki-67 high, whereas a Ki-67 labeling index of <10% is considered low. Diffuse moderate-to-strong expression of p53 in >75% of at least 12 epithelial cells (with or without intervening ciliated cells) or complete absence of staining has been shown to be compatible with a TP53 mutation either missense or nonsense (p53 MUT versus p53WT pattern in algorithm).












