CCND1 and neoplasm: Analyzing Cyclin D1, an important regulator of cell cycle progression, we did not find significant variation in the expression levels among groups (Figure 3d); however, a decreasing trend in both treated groups is consistent with the lower proliferation index of PNLs MB (Figure 1d), suggesting that repeated administrations of the DOX-carrying NPs would be able to inhibit tumor cell proliferation also during the late stage of MB development.