Phase I Multicenter, Open-label, Clinical and Pharmacokinetic Study of Plitidepsin in Combination with Sorafenib or Gemcitabine in Patients with Advanced Solid Tumors or Lymphomas to determine the maximum tolerated dose (MTD) and the recommended dose (RD), the pharmacokinetics (PK) of these combinations, drug-drug PK interactions, preliminary information on the clinical antitumor activity of these combinations in solid tumors,perform a preliminary pharmacogenomic (PGx) study of potential biomarkers of sensitivity/resistance to these drugs combinations and of prognostic markers of the treatment outcome in tumor tissue sample.