B and T Tumor-Infiltrating Lymphocyte Subtypes According to Subsite: A Colon Cancer Immunophenotyping Map

Area of Science:

• Oncology
• Immunology
• Pathology

Background:

• Colorectal cancer (CRC) prognosis is linked to tumor-infiltrating lymphocyte (TIL) subtypes.
• Differences in CRC prognosis based on tumor location (proximal vs. distal colon) are not fully understood.
• Investigating TIL subtypes (CD3+, CD8+, CD73+) stratified by primary tumor location is crucial.

Purpose of the Study:

• To investigate the prognostic value of CD3+, CD8+, and CD73+ TILs in colon cancer.
• To determine if the prognostic impact of TIL subsets differs based on primary tumor location.
• To correlate TIL expression with clinical and pathological characteristics stratified by tumor location.

Main Methods:

• Quantified CD3+, CD8+, and CD73+ TIL density in 100 colon cancer patients using immunohistochemistry and digital image analysis.
• Utilized QuPath and ImageJ for cell counting and staining intensity assessment.
• Performed statistical analysis, including ROC curves for cut-off values, correlation analysis, and Kaplan-Meier survival analysis.

Main Results:

• CD3+ T-cells were most abundant, predominantly in the right colon.
• CD3+ T-cell counts correlated with T stage and perineural invasion in left-sided tumors, and tumor grading in the right colon.
• Low CD3+ TILs associated with higher N stage and perineural invasion (left colon); low CD8+ TILs associated with higher T stage (left colon).

Conclusions:

• TIL subtypes in colon cancer exhibit significant variability based on primary tumor location.
• TIL expression is associated with distinct clinical and pathological characteristics depending on tumor site.
• This study is exploratory; larger validation is required before TIL densities can guide CRC therapy.