Evidence for Heterogeneous Nuclear Ribonucleoprotein K Overexpression in Oral Squamous Cell Carcinoma

The recent paper of Carpenter et al (2006b) in your journal identified hnRNP K as being overexpressed in colorectal cancer by proteomics, which has been confirmed by immunohistochemistry and tissue microarray analysis. Their study also showed that hnRNP K had an aberrant subcellular localisation in cancer cells. Although there were previous reports by Moumen et al (2005), suggesting that, in response to DNA damage, p53 inhibits hnRNP K ubiquitin-dependent proteasomal degradation, the study by Carpenter et al (2006a) could not, however, find any correlation between the expression of hnRNP K and p53 in colorectal cancer cells. We note the above observations with interest, as hnRNP K has a role in tumorigenesis and its expression has been found to be upregulated in several other cancers, including those of lungs and liver (Carpenter et al, 2006a)