Effect of flavopiridol and 4OH-Tam on expression of cell cycle regulatory proteins: A. Immunoblots of various cell cycle proteins in the presence and absence of flavopiridol and 4OH-Tam, after two days of treatment. B. αp21 immunocytochemistry of MON cells treated with: no drug (panel 1), 100 nM flavopiridol (panel 2), 5 μM 4OH-Tam (panel 3), or both 100 nM flavopiridol and 5 μM 4OH-Tam (panel 4). Note the strong nuclear staining in the drug treated cells (panels 2-4). C. Quantitation of MON cells with nuclear p21 using α-p21 immunocytochemistry after treatment with no drug, 100 nM flavopiridol, 5μM 4OH-Tam, or 100 nM flavopiridol and 5μM 4OH-Tam. Average values represent counting of more than 200 cells in four random fields for each treatment group.