- Hypermethylation of death-associated protein (DAP) kinase CpG island is frequent not only in B-cell but also in T- and natural killer (NK)/T-cell malignancies. Nakatsuka, S., Takakuwa, T., Tomita, Y., Hoshida, Y., Nishiu, M., Yamaguchi, M., Nishii, K., Yang, W.I., Aozasa, K. Cancer Sci. (2003)