Bortezomib With or Without Irinotecan in Treating Patients With Cancer of the Gastroesophageal Junction or Stomach

Inclusion Criteria

• •Patients must have histologically or cytologically confirmed adenocarcinoma of the GE junction or stomach, which is beyond the scope of surgical resection
• •Patients must have measurable disease, defined as at least one lesion that can be accurately measured in at least one dimension (longest diameter to be recorded) as \>= 20 mm with conventional techniques or as \>= 10 mm with spiral CT scan
• •Patients may have received adjuvant therapy for resected disease
• •* Patients who have received no prior systemic therapy for advanced disease are eligible to receive PS341 + irinotecan
• •* Patients are eligible for PS-341 as a single agent if they have received any number of prior regimens for gastric cancer
• •Life expectancy of greater than 6 weeks
• •ECOG performance status =\< 2 (Karnofsky \>= 60%)
• •Leukocytes \>= 3,000/uL
• •Absolute neutrophil count \>= 1,500/uL
• •Platelets \>=100,000/uL
• •Total bilirubin within normal institutional limits
• •AST(SGOT)/ALT(SGPT) =\< 2.5 X institutional upper limit of normal
• •Creatinine within normal institutional limits
• •When possible, patients will undergo an esophagogastroduodenoscopy (EGD) with biopsy prior to therapy then at 24 hours after starting PS-341
• •Women of child-bearing potential and men must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry and for the duration of study participation; should a woman become pregnant or suspect she is pregnant while participating in this study, she should inform her treating physician immediately
• •Ability to understand and the willingness to sign a written informed consent document