TS offer a simple and minimally invasive method to access components of the epidermis. TS have been applied broadly in dermatology research, but their widespread adoption has been limited by variability between protocols and a lack of standardization. For RNA extraction, we recommend using 20 TS and a commercial guanidinium thiocyanate lysis buffer with a scraper, then purification using a spin column kit. For psoriasis and koebnerizing dermatoses we advise caution if taking over 10 TS from nonlesional skin. There is no optimum protocol to extract protein, and methodology should be designed based on the target studied. The number of TS should correspond to the depth of target expression and abundance. For soluble proteins, we recommend starting with 10 min of sonication in PBS. For insoluble proteins, we recommend 30 min of sonication with a buffer containing 0·2% SDS in PBS. The addition of DTT should be considered if the yield is suboptimal (note that compatibility with downstream analysis kits should be checked). If both protein and RNA extraction are required from the same set of TS, TS 2–10 can be used for protein extraction and TS 11–20 for RNA. Wider sharing of protocols and yield data will allow TS to be more widely used as an alternative to biopsies.
This work was supported by a clinical training research fellowship MR/T008040/1 from the Medical Research Council, UK to A.H. S.S.T. is funded by the Newton Mosharafa fund. K.P.B. is funded by Barts Charity.
The British Journal of Dermatology. 2021;185(1):26-35. © 2021 Blackwell Publishing