Oulu University Horspital 1 article published in JoVE Cancer Research Fully Human Tumor-based Matrix in Three-dimensional Spheroid Invasion Assay Erika Naakka1, Katja Tuomainen1, Henrik Wistrand*1, Miila Palkama*1, Ilida Suleymanova1, Ahmed Al-Samadi1, Tuula Salo1,2,3,4 1Department of Oral and Maxillofacial Diseases, Clinicum, Faculty of Medicine, University of Helsinki, 2Cancer and Translational Medicine Research Unit, University of Oulu, 3Medical Research Center, Oulu University Horspital, 4Helsinki University Hospital Tumor microenvironment is an essential part of cancer growth and invasion. To mimic carcinoma progression, a biologically relevant human matrix is needed. This protocol introduces an improvement for the in vitro three-dimensional spheroid invasion assay by applying a human leiomyoma-based matrix. The protocol also introduces a computer-based cell invasion analysis.