Peripheral blood stem cells (PBSCs) were collected from 29 adult patients (median age 42 years, range 14-59 years) with breast cancer, germ cell tumor and malignant lymphoma after disease-oriented, conventional-dose chemotherapy combined with daily subcutaneous injections of low-dose (50 micrograms/m2 or 2 micrograms/kg) granulocyte colony-stimulating factor (G-CSF). The median number of colony-forming units-granulocyte macrophage (CFU-GM) collected in an apheresis was 2.37 (range 0-60.6) x 10(4)/kg body weight. Taking into consideration the minimum number of CFU-GM for hematopoietic reconstitution (at least 1 x 10(5) CFU-GM/kg), it was suggested that sufficient PBSCs could be collected by a few leukaphereses, although the cell yields of PBSCs tended to differ among the chemotherapeutic regimens. Twelve patients subsequently received high-dose chemotherapy followed by peripheral blood stem cell transplantation (PBSCT), including four receiving PBSCT alone and eight both PBSCT and autologous bone marrow transplantation (BMT). When compared with the 20 patients who received high-dose chemotherapy followed by autologous BMT alone, the median day of recovery of a neutrophil count > 0.5 x 10(9)/l and a platelet count > 20 x 10(9)/l was significantly shortened in those who received PBSCT (9 vs 12 days; P < 0.01 and 14 vs 30.5 days; P < 0.001), resulting in a lower platelet transfusion requirement (4.5 vs 9; P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)