Chemoradiotherapy plus tislelizumab for mismatch repair proficient rectal cancer with supraclavicular lymph node metastasis: A case report

Figure 1 ¹⁸F-FDG PET/CT image before and after treatment. A: ¹⁸F-FDG PET/CT image before treatment. The number is time of examination; B: Metastatic lymph node in the clavicle before treatment. The orange arrow indicates the lymph node; C: The rectal lesion before treatment. The lesion is indicated by the blue arrows; D: ¹⁸F-FDG PET/CT image after treatment. The number is time of examination; E: Disappearance of the metastatic lymph node after treatment; F: The rectal lesion with reduced uptake after treatment.

Figure 2 Histopathological analysis and immunohistochemical staining of the biopsy specimen. A: MLH1 is positive in tumor cells; B: MSH2 is positive in tumor cells; C: MSH6 is positive in tumor cells; D: PMS2 is positive in tumor cells; E: High expression of programmed cell death-ligand 1 in the specimen.

Figure 3 Immunohistochemical staining of CD8+ T cell and effector regulatory T cell before and after treatment. A: CD8+ T cell in tumor cells before treatment; B: effector regulatory T cell (eTreg) in tumor cells before treatment; C: CD8+ T cell in tumor cells after treatment; D: eTreg in tumor cells after treatment.