Objectives: Sperm-associated antigen 9 (SPAG9) has been suggested as a possible biomarker in several malignancies including thyroid cancer. We investigated the expression of SPAG9 mRNA in fine needle aspiration (FNA) material from papillary thyroid carcinoma (PTC) and benign thyroid nodules.
Study design: SPAG9 expression was assessed in 36 FNA samples corresponding to 16 PTC and 20 benign nodules using the original method detecting the SPAG9 transcript containing intron 21 (NCBI X91879). The presence of the BRAF V600E point mutation was also analyzed by pyrosequencing.
Results: Six of 16 (38%) PTC samples were positive for X91879 SPAG9 transcript compared to 8 of 20 (40%) benign samples (p = 0.88). Out of 12 BRAF-positive PTC, 3 (25%) also expressed the SPAG9 transcript compared to 3 out of 4 BRAF-negative PTC (75%; p = 0.12).
Conclusions: The X91879 SPAG9 transcript originally described does not appear to be overexpressed in FNA material from PTC or to be clinically relevant in the diagnosis of thyroid nodules.
Keywords: Cancer; Diagnosis; Fine needle aspiration; Sperm-associated antigen 9; Thyroid.