Two hypothetical concepts are discussed as means to cure cancer: 1) extinction of the neoplastic cell pool which forms the tumor and 2) induction of terminal differentiation to park tumor cells in growth arrest (1 ). Sodium butyrate (NaB) has been shown to promote differentiation of HL-60 cells to mature monocytes (2 )or an eosinophil-commited HL-60 subline to eosinophils(3 ).NaB also triggers terminal differentiation of keratinocytes(4 ).However, application of NaB to colon carcinoma cells (but not to normal colon cells) induces apoptosis(5 ). Therefore, a pharmacological agent that elicits differentiation in one cell type can trigger an entirely different response, apoptosis, in another.
