Study of Erlotinib in Combination With Dasatinib

Inclusion Criteria:

1. Patients with pathologically confirmed advanced or metastatic cancer that is refractory to standard therapy, relapsed after standard therapy, or who have had no standard therapy that induces a CR rate of at least 10% or improves survival by at least three months.
2. Measurable or non-measurable disease.
3. Patients must be \>/= 6 wks beyond treatment with a nitrosourea or mitomycin-C, \>/= 4 wks beyond other chemotherapy or external beam radiation therapy (XRT), and must have recovered to \</= Grade 1 toxicity for any treatment-limiting toxicity resulting from prior therapy. (Exception: patients may have received palliative low dose XRT one week before treatment provided it is not given to the only targeted lesions).
4. (continued from above) Also, patients who have received non-chemotherapeutic biological agents will need to wait at least 5 half-lives or 4 wks, whichever is shorter, from the last day of treatment.
5. Eastern Cooperative Oncology Group (ECOG) performance status \</= 2 (Karnofsky \>/= 60%)
6. Patients must have normal organ and marrow function defined as: absolute neutrophil count \>/=1,000/mL; platelets \>/=50,000/mL; creatinine \</= 2 X upper limit of normal (ULN); total bilirubin \</= 2.0; ALT(SGPT) \</= 3 X ULN; Exception for patients with liver metastasis: total bilirubin \</= 3 x ULN; ALT(SGPT) \</= 5 X ULN.
7. Women of childbearing potential and men must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry, for the duration of study participation, and for 30 days after the last dose.
8. Ability to understand and the willingness to sign a written informed consent document
9. For the MTD expansion cohort, patients will be eligible if they meet one of the following criteria: (I) Have an EGFR-sensitive mutation and have been previously treated with EGFR inhibitor therapy but have subsequently developed resistance, OR (II) Have an EGFR-resistant mutation, OR (III) Do not have an EGFR mutation, but have benefited from EGFR inhibitor therapy (including either \>/=4 months of stable disease \[SD\] OR a \>/= partial response \[PR\]).

Exclusion Criteria:

1. Patients with uncontrolled concurrent illness, including but not limited to: ongoing or active infection; altered mental status or psychiatric illness/social situations that would limit compliance with study requirements and/or obscure study results.
2. Uncontrolled systemic vascular hypertension (systolic blood pressure \> 140 mm Hg, diastolic blood pressure \> 90 mm Hg on medication).
3. Patients with clinically significant cardiovascular disease: history of cardiovascular accident (CVA) within 6 months, myocardial infarction or unstable angina within 6 months, or unstable angina pectoris.
4. Patients with colorectal carcinoma with tumors that demonstrate a Kirsten rat sarcoma (KRAS) mutation.
5. Pregnant or lactating women.
6. Patients with a history of bone marrow transplant within the previous two years.
7. Patients with a known hypersensitivity to any of the components of the drug products.
8. Patients who will be on treatment arm consisting of erlotinib and dasatinib should not be taking any drugs that are potent inhibitors or inducers of CYP34A
9. Patients unable to swallow oral medications or with pre-existing gastrointestinal disorders that might interfere with proper absorption of oral drugs.
10. Patients with major surgery within 30 days prior to entering the study.