Complement Detection in Human Tumors by Immunohistochemistry and Immunofluorescence

Area of Science:

• Oncology
• Immunology
• Biochemistry

Background:

• Tumors exhibit a complement-rich microenvironment involving various cell types.
• Tumor and stromal cells can produce diverse proteins, including complement components.

Purpose of the Study:

• To develop and describe immunohistochemistry (IHC) assays for identifying complement-producing cells and activation fragments in tumor sections.
• To enable investigation into the prognostic significance of local complement production and activation in cancer.

Main Methods:

• Development of immunohistochemistry (IHC) assays for paraffin-embedded human tumor sections.
• Utilizing immunofluorescence and IHC to detect complement proteins (C1q, C4, C3) and their activation fragments.
• Semi-quantification of staining patterns in large patient cohorts.

Main Results:

• Assays successfully identify local complement production (cytoplasmic staining) and activation fragments (cell surface staining) within tumors.
• Significant heterogeneity in complement staining observed within tumors and between patients.
• Established methods for analyzing complement's role in the tumor microenvironment.

Conclusions:

• The developed IHC assays provide a tool to study complement dynamics in the tumor microenvironment.
• Local complement production and activation are heterogeneous and warrant further prognostic investigation.
• These methods can advance understanding of complement's role in cancer progression and patient outcomes.