DISEASE CHARACTERISTICS:

• Histologically or cytologically confirmed advanced solid tumors or lymphoma

  • Disease considered incurable using standard treatment

PATIENT CHARACTERISTICS:

• ECOG performance status ≤ 2
• Life expectancy > 12 weeks
• WBC ≥ 3,000/mm^3
• Absolute neutrophil count ≥ 1,500/mm^3
• Platelet count ≥ 100,000/mm^3
• Total bilirubin normal
• AST/ALT ≤ 2.5 times upper limit of normal
• Creatinine normal OR creatinine clearance ≥ 60 mL/min
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception prior to and during study treatment
• No history of allergic reactions attributed to compounds of similar chemical or biologic composition to 3-AP (Triapine®) and/or gemcitabine hydrochloride
• No known glucose-6-phosphate dehydrogenase (G6PD) deficiency
• No 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 situation that would limit compliance with study requirements
• No pulmonary disease (e.g., dyspnea at rest, supplemental oxygen requirement, or baseline oxygen saturation < 92%)

PRIOR CONCURRENT THERAPY:

• Prior gemcitabine hydrochloride allowed if given as a standard 30-minute infusion

  • At least 4 weeks since prior gemcitabine hydrochloride
• Patient may have received < 2 lines of chemotherapy in the metastatic setting
• No prior 3-AP (Triapine®) or fixed-dose gemcitabine hydrochloride
• At least 6 weeks since prior nitrosoureas or mitomycin C
• More than 3 weeks since prior radiotherapy
• No other concurrent investigational agents
• No concurrent combination antiretroviral therapy in HIV-positive patients
• No other concurrent anticancer agents or therapies