INCLUSION CRITERIA

   - Basal cell carcinoma (BCC)

   - Ineligible for curative locoregional treatment and have either progressed on, did not
   tolerate, unwilling to try or ineligible for investigational smoothened antagonist
   such as vismodegib (GDC 0449), XL 139 (BMS 833923), IPI- 926, LDE225 and PF-04449913

   - Life expectancy estimate > 3 months

   - Performance status Eastern Cooperative Oncology Group (ECOG) 0-2

   - Absolute neutrophil count ≥ 1,500/mcL

   - Platelets ≥ 100,000/mcL

   - Total bilirubin within normal institutional limits

   - Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase
   [SGOT])/alanine aminotransferase (ALT) (serum glutamate pyruvate transaminase [SGPT])
   ≤ 2.5 x institutional upper limit of normal

   - Creatinine within normal institutional limits

   - Corrected QT interval (QTC) by 12 lead electrocardiogram (EKG) < 450 msecs

   - Serum potassium within normal limits

   - Magnesium within normal limits

   - Calcium within normal limits

   - Ability to understand and the willingness to sign a written informed consent document

   - Evaluable tumor and be potentially eligible for pre and post ATO tumor biopsy

   - Receiving potassium wasting diuretics or amphotericin, while not excluded, must be
   noted to have theoretically increased arrhythmia risks with ATO

EXCLUSION CRITERIA

   - Concurrent use of other Investigational agents

   - Cardiac arrhythmias

   - Uncontrolled intercurrent illness including, but not limited to, ongoing or active
   infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac
   arrhythmia, recurrent seizure history or psychiatric illness/social situations that
   would limit compliance with study requirements

   - Pregnant or lactating