Evaluation of Pathway Modulation by Raf, MEK, & Kinase Inhibitors

Inclusion Criteria: * Subjects who have not yet initiated but plan to undergo dosing with a Tyrosine Kinase inhibitor (TKI) or Raf inhibitor, either alone or with a MEK inhibitor, for treatment of metastatic melanoma, colon cancer, hepatic cell carcinoma, or thyroid cancer. * Individuals with normal skin and Fitzpatrick skin type II, III or IV. * Individuals who are willing to limit sun exposure to the body during the study period, and who agree to wear protective clothing and SPF 50 broad spectrum sunscreen or sunblock on exposed skin when they are outdoors. * Individuals who have the ability to understand and willingness to sign an informed consent before initiation of study procedures, after the nature of the study is explained to them and they have asked any questions. * Individuals with a Karnofsky Performance Status of at least 80%. Exclusion Criteria: * Individuals with any inflammation or irritation of the skin at the test area (buttocks), or any skin conditions felt by the study physician to contraindicate enrollment. * Individuals with a history of any skin cancer, melanocytic lesions, actinic keratoses or actinic damage in the test area are ineligible. History of such conditions at a body site other than the test area is not exclusionary if in the opinion of the study physician it will not pose a risk to the subject. * Individuals who are immunosuppressed by virtue of medication or disease, as determined by the examining study physician. This includes AIDS patients and subjects taking oral steroids. * Individuals with active infection, psychiatric illness, or other situations that in the opinion of the study physician limit compliance or interfere with the study regimen. * Individuals with a history of photosensitive diseases including, but not limited to, Lupus Erythematosus, pseudoporphyria, or other diseases that in the opinion of the study physician would pose a risk to the subject or interfere with the study. * Individuals who have used photosensitizing drugs within the last 30 days prior to study enrollment, or who will be using a photosensitizing drug during the time of the study. * Individuals who have used any topical medication other than emollients on the test area within 30 days prior to study enrollment. * Individuals who have used retinoids, steroids, 5-fluorouracil, Levulan, Vaniqua (eflornithine), Solaraze, or Imiquimod (Aldara®) anywhere on the body within 30 days prior to enrollment. * Individuals must not take mega-doses of vitamins. Mega-doses are defined as more than 5 capsules of standard multivitamins daily or more than the Tolerable Upper Intake Levels of Vitamins, as defined by the Institute of Medicine, National Academy of Sciences. Such vitamin therapy must be discontinued at least 30 days prior to study entry. * Individuals with a history of natural or artificial sun exposure to the buttocks within 30 days of study participation. * Individuals with Fitzpatrick skin type I * Individuals with Fitzpatrick skin type V or VI * Individuals enrolled in or who plan to enroll in a clinical intervention trial. There must be a 30-day period between completing a previous study and enrolling in this study. The Principal Investigator will have the option to consider an exception for patients on drugs of interest for the purpose of this study. * Individuals with a known allergy to lidocaine.