Inclusion Criteria:

- Stage III/B or IV squamous NSCLC

- Measurable disease

- Previously offered all standard chemotherapy regimens for advanced squamous cell lung
cancer

- ECOG performance status of 0 or 1

- Estimated life expectancy greater than 12 weeks

- Normal organ and marrow function

- Confirmed availability of archival pathology samples

- Agrees to discontinue St. Johns Wort

- Able to take medications by mouth

- Willing and able to use acceptable method of birth control for the entire study
period and for at least 4 weeks after the last dose of study drug

Exclusion Criteria:

- Pregnant or breast-feeding

- Chemotherapy or radiotherapy within 4 weeks prior to entering study

- Receiving any other investigational agents

- Known untreated or progressive brain metastases

- History of prior treatment with or allergic reactions attributed to compounds of
similar chemical or biologic composition to dasatinib, nilotinib or imatinib

- Taking medications known to be potent CYP3A4 inhibitors

- Currently taking H2 inhibitors or proton pump inhibitors

- Currently taking drugs or have taken drugs in the past 7 days that are generally
accepted to have a risk of causing Torsades de Pointes

- HIV positive

- Clinically uncontrolled hypertension (blood pressure > 160/110)

- Previous or concurrent malignancy except adequately treated basal or squamous cell
skin cancer, in situ carcinoma of the cervix, or other solid tumor treated
curatively, and without evidence of recurrence for at least 5 years

- Active and uncontrolled clinically significant infection

- Chronic gastrointestinal disease

- Acquired or congenital bleeding disorder or clinically significant gastrointestinal
bleeding within 3 months

- Supplemental oxygen required for current malignancy

- Evidence of symptomatic pleural effusions unless undergoing a therapeutic
thoracentesis as part of non-study care

- Individuals who are prisoners or who are compulsory detained for medical or
psychiatric reasons

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

- Hypokalemia or hypomagnesemia that cannot be corrected prior to dasatinib
administration