CD44 and neoplasm: The proliferative activity was lower in specimens treated with 4-MU than in controls and the proliferating cells were confined to the outer circumference of the large tumour cell clusters that tested positive for HA, CD44 and RHAMM (Figure 8A; proliferating cells in controls, 25% ± 3%; proliferating cells in sections of mice treated with 4-MU, 15% ± 3%; p < 0.05; n = 4-5).