This is a randomized, prospective study to evaluate the effects of preemptive pharmacogenomic (PGx) testing on opioid dosing decisions/selections and pain score in cancer patients.

Inclusion Criteria:

• Persons receiving ongoing oncology care at the University of Chicago Medical Center for whom near-future pain opioid pain medication therapy is anticipated
• Subjects must be at least 18 years of age.

Exclusion Criteria:

• Subjects taking an opioid at the time of enrollment, or within the past 30 days
• Subjects who are currently undergoing palliative radiation
• Subjects who have undergone, or are being actively considered for, bone marrow, liver or kidney transplantation.
• Subjects with a history of or active blood cancer (e.g., leukemia).
• Chronic kidney disease, as defined by Glomerular filtration rate (GFR) < 30/mL/min/1.73m2, due to the risk of decreased drug excretion.
• Liver dysfunction, as defined by the following laboratory values, due to the risk of decreased drug metabolism: Total bilirubin greater than or equal to1.5 mg/dL, Aspartate Aminotransferase (AST) and Alanine Aminotransferase (ALT) greater than or equal to 2.5 X upper limit of normal*. (*Aspartate Aminotransferase (AST) and Alanine Aminotransferase (ALT) \ greater than or equal to 5 X upper limit of normal if hepatic metastases are present).
• Inability to understand and give informed consent to participate in the opinion of the investigator
• Subjects who are known to be pregnant at the time of enrollment
• Subjects who have previously or are currently enrolled in another institutional pharmacogenomic genotyping study, or are known to have previously undergone pharmacogenomic genotyping for the gene(s) of interest via another commercial or other means.