DISEASE CHARACTERISTICS: Phase I: Histologically proven advanced, primary, or malignant solid tumors that are refractory to standard therapy or for which no curative therapy exists Androgen-independent prostate cancer Head and neck cancers Breast cancer Non-small cell lung cancer Colorectal cancer Ovarian cancer Esophageal cancer Bladder cancer Kidney cancer Other solid tumors Metastatic disease should not require palliative treatment within 4 weeks of enrollment Phase II: Histologically proven androgen-independent prostate cancer Serum testosterone less than 30 ng/mL Failed at least one prior chemotherapy regimen Progressive Minimum of 3 rising PSA values from baseline obtained at least 1 week apart OR Two rising PSA values more than one month apart AND At least 25% increase over range of values AND PSA at least 4 ng/mL No active CNS or epidural tumor Hormone receptor status: Not specified