Tumor immunophenotype: comparison between primary neoplasm and its metastases

Area of Science:

• Oncology
• Immunohistochemistry
• Cancer Metastasis Research

Background:

• Monoclonal antibodies (MAb) are established diagnostic tools and show promise for cancer immunotherapy.
• Tumor cells within a primary tumor can exhibit antigenic heterogeneity.
• The degree to which metastases maintain the immunophenotype of primary tumors is not well-established through large-scale studies.

Purpose of the Study:

• To investigate the immunophenotypic consistency between primary epithelial tumors and their corresponding metastases.
• To determine if the immunophenotype of metastases can be reliably predicted from the primary tumor.

Main Methods:

• Utilized immunohistochemistry (IHC) on 344 tissues from 54 epithelial malignancies, including primary tumors and metastases.
• Employed a panel of seven monoclonal antibodies (MAb) targeting various membrane and cytoplasmic antigens.
• Selected cases uniformly fixed and processed from single surgical procedures.

Main Results:

• A small percentage of metastases (5.5%) expressed antigens not present on the primary tumor.
• No cases showed complete loss of a primary antigen in all metastases.
• Phenotypic modifications were observed in 18.5% of cases across one or more metastases.

Conclusions:

• Tumor metastasis does not typically involve broad phenotypic variation.
• The immunophenotype of metastases can be reliably predicted based on the primary tumor's immunophenotype.
• Findings support the use of primary tumor immunophenotype for predicting metastatic characteristics in clinical practice.