Short report

Experimental Hematology & Oncology

, 1:34

Open Access This content is freely available online to anyone, anywhere at any time.

Pattern of antigen expression in metastases after radioimmunotherapy of a syngeneic rat colon carcinoma utilizing the BR96 antibody

  • Erika ElgströmAffiliated withDepartment of Oncology, Lund University Email author 
  • , Sophie E ErikssonAffiliated withDepartment of Oncology, Lund University Email author 
  • , Tomas G OhlssonAffiliated withDepartment of Medical Radiation Physics, Lund University
  • , Jan TennvallAffiliated withDepartment of Oncology, Lund UniversityDepartment of Oncology, Skåne University Hospital
  • , Rune NilssonAffiliated withDepartment of Oncology, Lund University

Abstract

Background

Repeated administration of antibody-based therapies such as radioimmunotherapy depends on preserved antigen expression in tumor lesions. The purpose of this study was to evaluate whether the antigen expression in metastases observed after radioimmunotherapy differs from that of untreated primary tumors.

Findings

30 of the 35 Brown Norway rats with syngeneic colon carcinoma treated with 400 MBq/kg 177Lu-DOTA-BR96 exhibited consistent complete response of the primary tumor. 13 animals developed metastases that were detected after treatment. The antigen expression was reduced in 17 of 23 metastases detected after radioimmunotherapy compared with untreated tumors. No tumors completely lacked positively stained tumor cells.

Conclusions

Although it was not possible to demonstrate that the antigen reduction is triggered by the radioimmunotherapy this result stress the importance of considering the risk of reduced antigen expression in metastases after radioimmunotherapy prior to further targeted therapies.

Keywords

Radioimmunotherapy Rat colon carcinoma 177Lu Antigen expression Metastasis