To determine the diagnostic accuracy of MMS, MMS data will be collected from six clinical groups, each with a preoperative diagnosis: 1) malignant melanoma (MM), 2) basal cell carcinoma (BCC), 3) squamous cell carcinoma (SCC), 4) pre-cancerous lesions (AK), 5) benign or atypical nevi, or 6) other lesions or conditions (rare skin cancers such as merkel cell carcinoma, and inflammatory conditions such as psoriasis). The aim is to collect MMS data from a minimum of 240 patients (40 patients for each of the 6 groups), which will be split to training and validation datasets. Since several biopsies are required to diagnose a single skin cancer, it is anticipated that the actual number of pre-cancerous, benign and inflammatory lesions sampled will be much higher than our target total of 240, to be around 300. We will also collect data from non-skin cancer skin conditions: 1) psoriasis, 2) eczema / dermatitis, 3) lichen planus and 4) lupus. For the non-skin-cancer part of the study, we will enroll 20 patients from each of the categories, with a total target of 80 patients.