The Relationship between Programmed Cell Death Receptor-1 Expression in Colon Tumoral Tissue and Clinical and Pathological Characteristics of Patients with Colon Cancer

Activatory or inhibitory immune checkpoints regulate the activity of the immune system. Programmed cell death receptor 1 (PD-1 is an inhibitory immune checkpoint that their overexpression reflects the exhaustion of the immune system. However, it is still unclear how it affects the prognosis of colorectal cancer (CRC). This study aimed to investigate the prognostic value of PD-1 in patients with CRC according to tumor location.

In a cross-sectional study during 2020-2021, a number of 136 patients with history of CRC who underwent surgery at Al-Zahra Hospital in Isfahan between 2013 and 2017 were selected and evaluated retrospectively. Immuno-histochemical staining of tissue samples was performed for PD-1 marker and the expression of this marker was determined in the center and invasive margins of the tumor. Data on survival and date of death of patients were completed through the patient file and confirmed through the civil registry.

High expression of PD-1 in invasive margin was significantly related to lower T stage (T1/2) in left tumors, low M stage (M0) in right tumors, absence of metastasis in right and left tumors, larger tumor size (≥ 5 cm) in right-sided tumors. The expression of this marker in any tumor areas was not significantly related to the survival of the patients.

The findings of this study showed that high expression of PD-1 is related to the lower stages of the CRC, but it is not a good indicator for the prognosis of patients with colon cancer.