Genes as Predictors of Response to Gemcitabine, Docetaxel, and Capecitabine (GTX) in Metastatic or Unresectable Pancreatic Cancer.

Inclusion Criteria: * Patients must have clinically documented unresectable or metastatic pancreatic cancer and histologic confirmation of the diagnosis with tumor. * Tissue from tumor must be available. This may be paraffin embedded tissue from previous biopsy/resection or if it is not available, a repeat biopsy must be performed. * Patients must agree to have a 20 cc blood sample drawn in addition to routine labs with each cycle of chemotherapy. * Patients must have measurable disease by clinical exam or radiologic studies, that is at least one lesion measurable in at least one dimension, measuring 20mm. If prior radiation therapy was administered, measurable disease must be outside the radiation field. * Patients may have received prior adjuvant chemotherapy and/or radiation therapy; this must have been completed at least 6 months prior to the initiation of therapy for metastatic disease. * Patients must have a Zubrod performance status of 0-2. * Peripheral Neuropathy must be less than grade 1 * Patients must have a predicted life expectancy of at least 12 weeks. * Patients must have a pre-treatment granulocyte count (i.e., segmented neutrophils + bands) of greater than 1,500/mm3, a hemoglobin level of greater than or equal to 9.0 gm/dl, and a platelet count of greater than 100,000/mm3. * Patients must have adequate renal function as documented by a calculated creatinine clearance greater than 60. * No major surgery within 1 month of starting study drug. Exclusion Criteria: * Patients who have received prior adjuvant therapy with more than one of the following agents: gemcitabine, docetaxel or capecitabine * Patients who have received prior treatment for metastatic or unresectable pancreatic cancer. * Patients may not have a history of an allergy to gemcitabine, taxanes or fluoropyrimidines and polysorbate 80. * Patients with any active or uncontrolled infection, including known HIV infection. * Patients with psychiatric disorders that would interfere with consent or follow-up. * Patients with a history of myocardial infarction within the previous six months or congestive heart failure requiring therapy. * Pregnant or lactating women. Men and women of reproductive potential may not participate unless they have agreed to use an effective contraceptive method while on treatment and for at least 3 months thereafter. * Presence of clinically apparent central nervous system metastases or carcinomatous meningitis * Patients with a history of seizures are ineligible. Patients receiving phenytoin, phenobarbital, or other anti-epileptic prophylaxis are ineligible. * Patients with any other severe concurrent disease, which in the judgment of the investigator would make the patient inappropriate for entry into this study.