PD0332991-induced changes in Rb phosphorylation and Ki-67 expression in pre- and on-treatment lymph node biopsies. (A) Percent change in expression in phospho-Rb (pS807/S811), total Rb and Ki-67 in the on-treatment biopsy compared with the pre-treatment biopsy (top panels) and representative immunohistochemical images from patient 3, who eventually achieved a complete response (bottom panels). (B) Percent change in expression in phospho-Rb (pS807/S811), total Rb, and Ki-67 in cyclin D1–positive cells in the on-treatment biopsy compared with the pretreatment biopsy and representative immunofluorescence images from patient 3 (bottom panels). Blue indicates DAPI staining; green, cyclin D1; and red/yellow, the indicated Rb or Ki-67 Ab.