Based on the literature, some genes like Gm42418, AY036118 and Malat1 are indicators of rRNA contamination or low quality cells and are suggested to be removed from the count matrix before normalization. I am dealing with a dataset that after removal of controversial genes (MT genes, Ribo, Gm42418, AY036118 and Malat1), a 30 to 40 percent of cells the remain to have very low library size (total UMI per cell), e.g. less than 500 total UMIs per cell. Will you filter out these cells as apparently the main content has been rRAN and MT genes? Are samples with high proportion of such cells reliable for the downstream analysis?