Centrosomal kinases, HsAIRK1 and HsAIRK3, are overexpressed in primary colorectal cancers

Members of the recently identified family of Homo sapiens Aurora/Ipl1-relat ed kinases (HsAIRKs), homologous to chromosome segregation kinases, fly Aur ora and yeast Ipl1, are highly expressed during M phase, and have been sugg ested to regulate centrosome function, chromosome segregation, and cytokine sis, In the present study, immunohistochemical analyses were performed of H sAIRK1 and HsAIRK3 expression in 78 primary colorectal cancers and 36 color ectal adenomas as well as 15 normal colorectal specimens. In normal colon m ucosa, some crypt cells showed weak positive staining in 10 and 12 out of 1 5 cases for HsAIRK1 and HsAIRK3, respectively, the remaining cases being ne gative. Elevated expression of HsAIRK1 was observed in 53 (67.9%) of the co lorectal cancers, and of HsAIRK3 in 40 (51.3%), Furthermore, colorectal ade nomas showed high expression of HsAIRK1 and HsAIRK3 in 11 (30.6%) and 7 (19 .4%) cases, respectively, thus being intermediate between colorectal cancer s and normal colorectal mucosa, Interestingly, HsAIRK1 overexpression was s ignificantly associated with pT (primary tumor invasion) and p53 accumulati on in colorectal cancers. There was no significant correlation between prol iferating cell nuclear antigen-labeling index (PCNA-LI) and the levels of t hese proteins. The results suggest that overexpression of HsAIRK1 and HsAIR K3 might be involved in tumorigenesis and/or progression of colorectal canc ers.