Effect of cactus pear extracts on growth of human cervical, ovarian, and bladder cancer cells in monolayer cultures. Cells were grown for 1, 3, or 5 days in the absence (control) or presence of 0.5, 1, 5, 10, or 25% of cactus pear extracts in (a.) immortalized cervical cells and cervical cancer cells; (b.) immortalized ovarian cells and ovarian cancer cells; and (c.) bladder cancer cells. Values are means ± SD of triplicate cultures. The percentage of growth inhibition (GI) was calculated using the equation: % GI = (1-Nt/Nc) × 100; where Nt and Nc represent the numbers of cells in treated and control cultures, respectively.