Background: Thyroid cancer is the most commonly reported endocrine malignancy, and its increased incidence has been the highest in all human tumors in recent decades. To investigate the mechanism of papillary thyroid cancer (PTC) occurrence and progression, we performed RNA sequencing and found an upregulated gene, LAMB3 . However, the biological function of LAMB3  is still not clear.
Materials and methods: We analyzed LAMB3  expression using The Cancer Genome Atlas (TCGA) database and hypothesized LAMB3  to be a gene associated with PTC. To test this hypothesis, we collected 89 pairs of thyroid nodules and adjacent normal thyroid tissues (56 pairs of PTCs, 33 pairs of benign thyroid nodules). Afterward, we performed real-time quantitative polymerase chain reaction (RT-qPCR) to investigate LAMB3  expression in thyroid nodule patients, and then analyzed clinicopathologic features. We performed proliferation, colony formation, migration, and invasion assays to determine the function of LAMB3  in PTC.
Results: We demonstrated that LAMB3  plays oncogenic roles in PTC. The relative expression of LAMB3  is significantly upregulated in PTC compared with matched thyroid normal tissues in validated cohort and TCGA cohort (P <0.001). We also checked area under the curve (AUC of receiver operator characteristic [ROC]) of 97.3% for validated cohort and 90.1% for TCGA cohort to differentiate PTC tumors from normal tissues. In clinicopathologic feature analysis, we found that upregulated LAMB3  is closely related to lymph node metastasis (P =0.018). Furthermore, knockdown of LAMB3  inhibited the proliferation, colony formation, migration, and invasive capacity of PTC.
Conclusion: This study indicated that LAMB3  is a gene associated with PTC.
Keywords: papillary thyroid cancer, LAMB3 , PTC