A Phase I/II Study of Oblimersen Plus Cisplatin and Fluorouracil in Gastric & Esophageal Junction Cancer

Inclusion Criteria:

* Histologically or cytologically confirmed adenocarcinoma of the esophagus, gastro- esophageal junction, or stomach; patients with squamous cell carcinoma of the esophagus will also be eligible, patients must have locally advanced, recurrent or metastatic disease, not amenable to complete surgical resection or definitive radiation therapy
* Measurable and/or evaluable disease
* May have had prior surgery, radiation therapy, combined modality chemo- radiation, or at most one prior chemotherapy regimen for advanced, recurrent or metastatic disease;
* Life expectancy of greater than 12 weeks
* ECOG performance status =\<2 (Karnofsky \>= 60%)
* Absolute neutrophil count \>= 1,500/uL
* Platelets \>= 100,000/uL
* Total bilirubin within normal institutional limits
* Creatinine =\< 1.5 OR creatinine clearance \>= 60 mL/min/1.73 m\^2 for patients with creatinine levels above institutional normal
* Ability to understand and the willingness to sign a written informed consent document
* Patients with accessible tumors are obliged to participate in biopsies 1 and 2; accessible tumors are defined as tumors reachable by EGD, or metastases, which, in the opinion of the treating physician can be biopsied with commonly utilized biopsy methods (such as CT guided biopsy); biopsy #3 on day 6 is optional; patients who do not have have accessible tumor tissue may participate in the study if at least one tumor deposit is measurable

Exclusion Criteria:

* Patients who have had chemotherapy or radiotherapy within 21 days (6 weeks for nitrosoureas or mitomycin C, two weeks if prior treatment was a weekly regimen) prior to entering the study or those who have not recovered from adverse events (grade 2 or worse) due to agents administered earlier
* Patients who have had photodynamic therapy within 4 weeks of proposed study entry will be excluded; patients will be allowed to receive concurrent photodynamic therapy for obstruction untreatable by stent, laser, or dilation; patients who do require concurrent photodynamic therapy and who are participating in the serial biopsy portion of the study must wait until after cycle 1 and its biopsies are completed
* Patients may not be receiving any other investigational agents
* Patients with known brain metastases should be excluded from this clinical trial because of their poor prognosis and because they often develop progressive neurologic dysfunction that would confound the evaluation of neurologic and other adverse events
* History of allergic reactions attributed to compounds of similar chemical or biologic composition to anti- sense oligonucleotides, cisplatin, fluorouracil or other agents used in the study
* Patients may not have received G3139 previously
* Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements
* Pregnant women are excluded from this study because G3139 is an anti- sense oligonucleotide agent with the potential for teratogenic or abortifacient effects; because there is an unknown but potential risk for adverse events in nursing infants secondary to treatment of the mother with G3139, breastfeeding should be discontinued if the mother is treated with G3139; these potential risks may also apply to other agents used in this study
* Because patients with immune deficiency are at increased risk of lethal infections when treated with marrow-suppressive therapy, HIV-positive patients receiving combination anti-retroviral therapy are excluded from the study because of possible pharmacokinetic interactions with G3139 or other agents administered during the study; appropriate studies will be undertaken in patients receiving combination anti-retroviral therapy when indicated