What role does immunohistochemistry play in the diagnosis of tumors?

Immunohistochemistry (IHC) is a vital laboratory technique used in the diagnosis of tumors, primarily through the analysis of protein expression patterns within tissue samples. The correct answer emphasizes that IHC helps to determine the specific type of tumor based on these protein expressions.

Tumors can vary significantly in their histological features and biological behavior, and the proteins expressed by these tumors can offer critical insights into their identity and classification. For example, different types of tumors may express distinct protein markers, such as epithelial markers in carcinomas or neuroendocrine markers in neuroendocrine tumors. By using specific antibodies that bind to these proteins, pathologists can identify the presence and pattern of expression of these markers, helping to classify the tumor correctly. This classification is essential for diagnosis, prognosis, and guiding treatment decisions.

The other options may touch on related topics in pathology but do not accurately describe the principal function of immunohistochemistry in tumor diagnosis. For instance, while genetic mutations can be identified using molecular techniques, identifying them is not the primary role of IHC. Similarly, IHC is not employed to confirm infections or assess a patient's immune response directly, as those aspects typically involve different diagnostic methods and assessments. The principle focus remains on tumor classification