This invention provides compounds, compositions and methods for modulating the expression of human GST-π using RNA interference. The RNA interference molecules can be used in methods for preventing or treating diseases such as malignant tumor. Provided are a range of siRNA structures, having one or more of nucleotides being modified or chemically-modified. Advantageous structures include siRNAs with 2-deoxy nucleotides located in the seed region, as well as other nucleotide modifications.本發明提供利用RNA干擾以調控人麩胱甘肽S轉移酶Pi(GST-π)之表現的化合物、組成物及方法。RNA干擾分子可用於預防或治療疾病(諸如惡性腫瘤)的方法。本發明提供一系列具有一或多個經修飾或經化學修飾之核苷酸的siRNA結構。有利之結構包括具有位於種子區之2-脫氧核苷酸及其他核苷酸修飾的siRNA。