This study is designed to add to the safety profile data as well as assessing biologic efficacy parameters. It will include 24 individuals with biopsy proven, resectable, stage I-III esophageal cancer. Because there may be immune responses attributable to the gene therapy vector itself, independent of the CD40L transgene, this part of the study is designed in a randomized, blinded fashion to compare intratumoral administration of the AdcuCD40L vector compared to a placebo. Because there are likely differences over time in the pattern of the biologic response to the expression of CD40L in the tumor (including activation and trafficking of DC, and recruitment and activation of immune cells), this study will include 2 "time" cohorts (based on the time between administration of the AdcuCD40L vector and the time of surgery to remove the tumor). Using Weill-IRB protocol #0011004683 dose escalation study to determine the highest non-toxic dose of the AdcuCD40L vector, this dose (likely 10^11 particle units) will be used for all individuals enrolled in this efficacy study. The placebo will be the salt water-sugar solution used as a vehicle for the vector. Since there is no evidence that delay of surgery for solid tumors for 15 days following diagnosis alters the prognosis, surgery for removal of the primary tumor will be carried out at either 5 or 15 days after administration of the vector (n= 12/group, including n=6 receiving the AdcuCD40L vector, and n=6 receiving placebo). This will permit assessment of the resulting data (in a randomized, blinded fashion) and the biologic responses to the AdCUCD40L vector over time. In addition to safety/toxicity parameters, the primary tumor, regional and distant nodes removed at the time of surgery, and peripheral blood will be assessed for biologic parameters relevant to responses to the AdcuCD40L vector.