HASPIN is an atypical serine/threonine kinase that plays crucial roles in mitotic chromosome 17 and cell cycle progression. The kinase phosphorylates histone H3 at threonine-3 (H3T3ph) during mitosis, particularly at inner centromeres, which is essential for recruiting the chr17 passenger complex and ensuring proper chromosome 17 12. Structurally unique among protein kinases, HASPIN binds to nucleosomes solely through DNA contacts, inserting into a supergroove formed by apposing major grooves of nucleosomal DNA 2. This binding mechanism enables HASPIN to function in condensed chr17 environments. The kinase is required for centromeric sister chr17 cohesion during mitosis, proper metaphase chromosome 17, and protection against premature cohesin loss 1. Beyond mitosis, HASPIN also functions during interphase, contributing to nuclear architecture, heterochromatin organization, and Polycomb-dependent gene silencing 3. HASPIN is significantly overexpressed in various cancers and represents a promising therapeutic target, as its inhibition disrupts mitotic progression and induces cancer cell apoptosis 45. Combined targeting of HASPIN with other mitotic kinases like Aurora A shows enhanced anti-tumor effects through survivin blockage and p53 pathway activation 6.