Molecular Markers for Thyroid Cancer Diagnosis: Insights from MAPK Pathway Gene Expression Analysis

Abstract

Background and Objectives: Thyroid cancer is the prevailing endocrine malignancy, with incidence growing over the last decades in the world. The current diagnostic techniques often yield inconclusive results, emphasizing the need for more effective diagnostic approaches. Molecular profiling emerges as a promising avenue for carcinoma differentiation, offering precise insights to guide patient selection for surgical intervention. This study aimed to identify molecular markers in thyroid cancer through the expression analysis of genes within the MAPK pathway, aiming to enhance the sensitivity and specificity of carcinoma diagnosis. Methods: Through a comparative analysis of malignant and benign thyroid samples, we identified 46 genes of the MAPK pathway that exhibited differential expression by PCR array analysis. Results: Validation through RT-qPCR and in silico analysis using TCGA confirmed significant results for CCNA1, CDKN1C, CREB1, FOS, HSPA5, JUN, MAP2K6, and SFN genes identified in our cohort, reinforcing the relevance of these biomarkers. Specifically, noteworthy are our findings regarding the potential diagnostic value of CCNA1 and SFN genes in papillary thyroid carcinoma, while the reduced expression of CDKN1C, FOS, and JUN genes in follicular carcinoma suggests their value in distinguishing the thyroid pathologies. Conclusions: This study identifies promising diagnostic markers, namely CCNA1, CDKN1C, FOS, JUN, and SFN genes, which have the potential to enhance clinical decision-making in thyroid cancer.

Keywords: MAPK pathway; diagnostic; gene expression; thyroid carcinomas.

Figure 1

Differential expression of MAPK pathway-related genes in thyroid lesion samples analyzed by PCR array. Out of the 84 genes examined, 46 genes showed significant differential expression (fold change ≥ 2 for upregulation or ≤0.5 for downregulation, with p < 0.05). (a) Analysis 1: malignant tumors (PTC and FTC) (group 2) vs. normal thyroid and benign tumors samples (group 1); (b) Analysis 3: PTC samples (group 4) vs. group 1; (c) Analysis 4: FTC samples (group 5) vs. group 1; (d) Analysis 5: FTC (group 5) vs. PTC samples (group 4). Bars represent the average fold change, with min (minimum) and max (maximum) values indicating variability among samples. The exact fold-change values and statistical details for each gene are provided in Supplementary Table S1.

Figure 2

Expression analysis of candidate diagnostic markers in thyroid cancer. The relative expression levels of CCNA1, CDKN1C, CREB1, FOS, HSPA5, JUN, KSR1, MAP2K6, MAPK8IP2, and SFN were determined by quantitative RT-qPCR in thyroid samples. The genes displaying differential expression are shown. (a) Analysis 1: MT (group 2) vs. BT samples (group 1); Analysis 3: (b) PTC (group 4) vs. BT samples (group 1); (c) Analysis 4: FTC (group 5) vs. BT samples (group 1); Analysis 5: (d) FTC (group 4) vs. PTC samples (group 5). Each gene was analyzed in duplicate, and expression levels were normalized to the reference gene MRLP19 to ensure consistency across all samples. Relative quantification (RQ) was used to represent gene expression levels. BT: normal thyroid and benign tumor samples, MT: malignant tumors (PTC and FTC), PTC: papillary thyroid carcinoma, and FTC: follicular thyroid carcinoma. Median gene expression levels for each sample group are presented. All genes showed statistically significant differential expression, with p < 0.05, as determined by the Mann–Whitney test: * p < 0.05, ** p < 0.01, *** p < 0.001.