Patients diagnosed with metastatic solid malignancies (SM), who have responded or whose disease remains stable following first line systemic therapy, and without available, potential curative therapeutic options, will be candidates for this Phase I/II study. Potentially eligible patients who agree to participate and sign a consent form will have their neoplastic cells and/or blood analyzed for the expression of a specific panel of Tumor Associated Peptide Antigens (TAPAs), including Sp17, ropporin, AKAP-4, PTTG1, Span-xb, Her-2/neu, HM1.24, NY-ESO-1 and MAGE-1. Patients whose tumors express one (1) or more of these TAPAs will receive three (3) days of subcutaneous Granulocyte Macrophage Colony Stimulating Factor (GM-CSF) to increase bone marrow production of monocytes and dendritic cell (DC) precursors, and whole blood will be obtained by phlebotomy and/or leukapheresis for generation of autologous DCs. Patient's DCs will be generated in Kiromic's Cell Processing Good Manufacturing Process (GMP) facility, according to established Standard Operating Procedures, and activated by pulsing/loading them with the TAPA(s) relevant for each particular patient. Patients will receive five (5) days of low-dose cyclophosphamide prior to each vaccination with TAPA-pulsed DCs to decrease Treg activity. TAPA-pulsed DCs will be administered at a fixed dose of up to 1 X 107 DCs at least two (2) days following cyclophosphamide administration. DC vaccination schedule will be once every fourteen (14) days via subcutaneous (SC) and intradermal (ID) injections for a total of 6 vaccinations. Low dose GM-CSF will also be administered SC for five (5) consecutive days, starting three (3) to six (6) hours after each TAPA-pulsed DC treatment, to optimize immune responses. Patients will be followed on a weekly basis (or more frequently if required) to evaluate treatment-related toxicity. Immune responses and anti-tumor responses will be evaluated per protocol specifications. Continuation and stopping rules for the study will be defined based on toxicity/tolerability (Phase I) and/or immune responses (Phase II).