Inclusion Criteria:

- Patients must have cytologically or pathologically verified diagnosis of gastric
cancer; patients must have locally advanced or distant metastatic disease (either
recurrent or at primary diagnosis) that is not surgically curable

- The pathologic confirmation of gastric cancer may be made from the metastatic
site; biopsy of the primary tumor is not necessary; patients with pathologic
confirmation of cancer from a metastatic site, along with clinical documentation
of gastric involvement and no evidence of another primary are also eligible

- Eligible pathologic type: patients may have any histological subtype including
adenocarcinoma NOS, papillary carcinoma, adenocarcinoma, intestinal type, clear
cell adenocarcinoma, mucinous carcinoma, signet ring cell carcinoma,
undifferentiated carcinoma, carcinoma NOS; patients must not have carcinoid
tumors or sarcomas

- Patients must have measurable disease; x-rays, scans, or physical examinations for
measurable disease must have been completed within 28 days prior to registration;
x-rays, scans or physical examinations for non-measurable disease must have been
completed within 42 days prior to registration,; all disease must be assessed

- Patients must be willing to have specimens submitted; the paraffin embedded specimens
must be available for submission

- Patients may have had prior surgery for their gastric cancer; patients must be at
least 2 weeks beyond surgery, and recovered from all effects of surgery

- Patients may have received prior chemotherapy, hormonal therapy, immunotherapy,
radiation or chemoradiotherapy as neoadjuvant or adjuvant treatment but this must
have been completed at least 6 months prior to documented recurrence or metastatic
disease; patients must not have received previous treatment for metastatic disease

- If patient received radiation therapy, the site of measurable disease must be
outside of the radiation field

- Patients must not have had prior therapy with EGFR targeting therapies

- Patients must have a Zubrod performance status of 0-1

- Leukocytes >= 3,000/mcl

- Platelets >= 100,000/mcl

- AGC >= 1,500/mcl

- Serum transaminase (SGOT or SGPT) =< 2.5 x IULN; patients with liver metastases must
have SGOT/SGPT =< 5 x IULN

- Bilirubin =< IULN

- Serum creatinine =< IULN OR measured creatinine clearance > 60 mL/min OR estimated
creatinine clearance> 60 mL/min

- Patients must have cardiac ejection fraction within the institutional range of normal
as measured by echocardiogram or MUGA scan; note that baseline and on treatment scans
should be performed using the same modality and preferably at the same institution

- Patients must either be able to swallow and/or receive enteral medications via
gastrostomy feeding tube; patients with intractable nausea or vomiting are not
eligible; patients with GI tract disease resulting in an inability to take oral
medication, malabsorption syndrome, a requirement for IV alimentation, prior surgical
procedures affecting absorption, or uncontrolled inflammatory GI disease (e.g.,
Crohn's, ulcerative colitis) are not eligible

- Patients must not have a history of allergic reactions attributed to compounds of
similar chemical or biologic composition to GW572016

- There must be no plans for the patient to receive concurrent chemotherapy, hormonal
therapy, radiotherapy, immunotherapy or any other type of therapy for treatment of
their cancer while on this protocol

- HIV-positive patients receiving combination anti-retroviral therapy are excluded from
the study because of possible pharmacokinetic interactions with GW572016

- Pregnant or nursing women are not eligible because of the risk of fetal harm; nursing
women may participate only if nursing is discontinued, due to the possibility of harm
to nursing infants from this treatment regimen; women/men of reproductive potential
must have agreed to use an effective contraceptive method

- No other prior malignancy is allowed except for the following: adequately treated
basal cell or squamous cell skin cancer, in situ cervical cancer, adequately treated
stage I or II cancer from which the patient is currently in remission or any other
cancer from which the patient has been disease-free for 5 years

- If day 28 or 42 falls on a weekend or holiday, the limit may be extended to the next
working day

- In calculating days of tests and measurements, the day a test or measurement is
done is considered day 0; therefore, if a test is done on a Monday, the Monday
four weeks later would be considered day 28; this allows for efficient patient
scheduling without exceeding the guidelines

- All patients must be informed of the investigational nature of this study and must
sign and give written informed consent in accordance with institutional and federal
guidelines

- At the time of patient registration, the treating institution's name and ID number
must be provided to the Statistical Center in order to ensure that the current
(within 365 days) date of institutional review board approval for this study has been
entered into the data base