TABLE 1.

Summary of p53 responses to actinomycin D (Act-D), DFX, and CPT treatment in normal (MRC-5) and tumor (RKO, MCF-7, and U2OS) cells

Parameter	Valuea
	Act-D		DFX		CPT
	Normal	Tumor	Normal	Tumor	Normal	Tumor
Serine 15 phosphorylation	−	−	+	+	+	+
Serine 20 phosphorylation	−	−	−	−	+	+
p21 expression	+	+	±	−	+	+
MDM2 expression	+	+	+	−	−	−
Cytoplasmic p53	−	−	±	+	−	−

^a+, present; −, absent; ±, present at low levels.