乳腺癌起源于乳腺上皮細胞，原因是乳腺上皮細胞發生基因改變，導致隨后組織穩態喪失。科學家們經過大量研究將乳腺上皮細胞分為幾個不同的亞群，但依然無法完全了解上皮細胞異質性和分化譜。

加州大學歐文分校（University of California, Irvine）的科學家，在最新一期Nature Communication上發表文章，采用單細胞mRNA測序(ScRNAseq)分析來自7個不同乳腺增生病人的25,790個人乳腺上皮細胞的轉錄組，使用無偏聚分析揭示了三種不同的上皮細胞群的存在，一種是基底細胞，另一種是導管腔上皮細胞，分為激素分泌型L1和激素反應L2型細胞。

文章作者從單細胞測序數據發現，KRT8在L2型細胞中比L1性表達水平高。

  為了闡述KRT8蛋白質表達異質性，作者選擇了ProteinSimple Milo單細胞western blot。Milo可將細胞分為三個亞群：陰性，低表達，高表達。并可以準確計算各亞群細胞的百分比即數量。

L2 was also characterized by higher levels of KRT8 than L1

 To quantify protein expression in individual cells, we utilized a recently developed single-cell western blot application (ProteinSimple, Milo), which performs electrophoretic separation of the protein content of about 2000 cells per chip and subsequently probed with fluorescently labeled antibodies.

Applying single-cell western blotting to luminal and basal cells isolated by FACS identified three cell states, namely KRT8-negative, -low, and -high , which illustrates the usefulness of single cell Western blotting as a quantitative validation tool downstream of scRNAseq analyses.

單細胞基因測序+Milo單細胞western blot組合，可以從基因水平和蛋白質水平完整解析細胞異質性，闡述腫瘤發生，干細胞發育等關鍵生命醫學問題。