title: RNA-seq of Homo sapiens: normal scar skin
design: This study was approved by the Medical and Ethics Committees of Dermatology Hospital, Southern Medical University, and each patient signed an informed consent before enrolling in this study. Keloid tissues were harvested during plastic surgery from three patients confirmed to have clinical evidence of keloid. No patient had received chemotherapy or radiotherapy prior to surgery. Normal scar tissues were obtained from two patients who underwent elective scar resection surgery. Excised skin was immersed in physiological saline and then transferred to the lab immediately. The skin tissue was washed twice with PBS. After removal of the adipose tissue under the reticular dermis, the samples were cut into 5 mm diameter pieces and incubated with dispase II (Sigma) for 2 h at 37C. The epidermis was peeled off and discarded and the dermis was minced into small pieces and digested at 37C for 2 hours using Collagenase IV (YEASEN, China). The resulting cell suspension was filtered through a 70m cell strainer (BD Falcon), and centrifuged at 1500 rpm for 10 min. The supernatant was removed and the pellet was washed once with PBS at 1500 rpm for 5 min. The pellet was then resuspended in PBS+1% FBS for flow cytometry.