[00153] Described herein are methods and compositions for determining whethera particular cancer is resistant to or susceptible to a histone deacetylase inhibitoror to histone deacetylase inhibitors. The methods include analysis of the expressionlevels of at least four biomarker genes associated with response to a histonedeacetylase inhibitor. Also described herein are methods and compositionsfor increasing the likelihood of a therapeutically effective treatment in apatient, comprising an analysis of the expression levels of at least four biomarkergenes associated with response to a histone deacetylase inhibitor. Also describedherein are isolated populations of nucleic acids derived from a cancer sensitiveto or resistant to a histone deacetylase inhibitor. Further described are kitsand indications that are used in conjunction with the aforementioned methodsand compositions.
