Immunomorphological Patterns of Chaperone System Components in Rare Thyroid Tumors with Promise as Biomarkers for Differential Diagnosis and Providing Clues on Molecular Mechanisms of Carcinogenesis

SIMPLE SUMMARY: Differential diagnosis by optical microscopy on biopsies of low-incidence tumors of the same organ can be difficult, hampering patient management, particularly in the many places around the world lacking advanced facilities for cancer diagnosis beyond a histopathology laboratory. Examples of these tumors are the Hurthle cell, anaplastic, and medullary carcinomas of the thyroid. Currently, there are no specific biomarkers detectable by optical microscopy for any of them. We study the Chaperone System of these tumors by immunohistochemistry to determine if its components show distinctive levels and distribution patterns. Here we report that the molecular chaperones Hsp27, Hsp60, and Hsp90, show quantitative levels and distribution patterns different for each tumor and different from those of a benign thyroid pathology, goiter. Therefore, the reported methodology offers a promising tool to diagnose these three malignancies, and for revealing clues about the role of the three chaperones in carcinogenesis of thyroid tissue. ABSTRACT: Hurthle cell (HC), anaplastic (AC), and medullary (MC) carcinomas are low frequency thyroid tumors that pose several challenges for physicians and pathologists due to the scarcity of cases, information, and histopathological images, especially in the many areas around the world in which sophisticated molecular and genetic diagnostic facilities are unavailable. It is, therefore, cogent to provide tools for microscopists to achieve accurate diagnosis, such as histopathological images with reliable biomarkers, which can help them to reach a differential diagnosis. We are investigating whether components of the chaperone system (CS), such as the molecular chaperones, can be considered dependable biomarkers, whose levels and distribution inside and outside cells in the tumor tissue could present a distinctive histopathological pattern for each tumor type. Here, we report data on the chaperones Hsp27, Hsp60, and Hsp90. They presented quantitative levels and distribution patterns that were different for each tumor and differed from those of a benign thyroid pathology, goiter (BG). Therefore, the reported methodology can be beneficial when the microscopist must differentiate between HC, AC, MC, and BG.