CALML6 as a potential diagnostic marker for thyroid cancer promotes thyroid cancer cell proliferation via modulating the immune microenvironment.

PURPOSE: CALML6 is an inflammation-related gene, and its expression may be associated with cancer. Here we evaluated the role of CALML6 expression in papillary thyroid carcinoma (PTC).

METHODS

We utilized databases such as The Cancer Genome Atlas (TCGA), Genotype-Tissue Expression Project (GTEx) and UALCAN to evaluate the relationship between CALML6 expression and clinicopathological features in thyroid cancer. Immunohistochemical assays were used to observe CALML6 expression in thyroid cancer tissues. The role of CALML6 in PTC cells was investigated using RNA interference.

RESULTS

We found CALML6 expression was lower than normal and associated with extrathyroidal extension, lymph node metastasis, pathological T stage, tall cell PTC and the expressions of immune checkpoint genes CD274 and PDCD1LG2 in THCA. Additionally, Immunohistochemical staining showed that CALML6 expression was significantly upregulated in thyroid cancer tissues. RNAi analysis showed that CALML6 knockdown significantly reduced cell growth and blocked the cell cycle of PTC cells.

CONCLUSIONS

Our results suggest that CALML6 may be a novel diagnostic marker for PTC that is closely associated with the invasive and tall cell subtypes, and it may be a potential target for immunotherapy.