Endocrine Abstracts

The objectives: To evaluate the diagnostic efficiency of the HBME-1 expression test on cytological samples with Bethesda categories III, IV, and V in the differential diagnosis of thyroid nodular lesions.

Materials and methods: The data of 14 patients with thyroid nodular lesions and cytological Bethesda categories III, IV, and V (" gray zone ") were analyzed. The HBME-1 expression was determined by the results of immunocytochemical (IC) and immunohistochemical (IHC) staining with mouse monoclonal antibodies against human HBME-1: Group I (n =9) - HBME-1 positive, Group II - HBME-1 negative. The HBME-1 expression grade was calculated as the sum of the score for staining intensity and cytoplasmic positive cells square (0 points – colorless, 1 - weakly pronounced yellow, 2 - moderately pronounced yellow, and 3 - brightly pronounced brown) and the score for the percentage of positive cells (0 - 0%; 1–25%; 2 - 26–50%; 3 - 51–75%; 4 - 76–100%) in the IHC sample. HBME-1 positive result was considered with an IHC score >6 points.

Results: According to the postoperative histological staining, the following diagnoses were made: nodular goiter (NG) – 6 and 0, follicular tumor of uncertain malignant potential (FT-UMP) – 3 and 1, differentiated thyroid cancer (DTC) – 0 and 4 (papillary TC – 3, follicular TC – 1) in the I and II groups, respectively. Patients with Bethesda ІІІ (n =5) were postop diagnosed: Group I (n =4) - NG; Group II (n =1) – FT-UMP. Patients with Bethesda IV (n =5): Group I (n =3) - NG was in 2 patients and FT-UMP - in 1; Group II (n =2) - DTC (papillary TC -1, follicular TC -1). Bethesda V (n =4) cytology: Group I (n =2) with FT-UMP; Group II (n =2) with DTC (papillary form). ROC analysis showed that the positive predictive value (PPV) of the HBME-1 expression test was 80% (CI 83.4% -96.4%), and diagnostic efficiency - 92.9% (CI 66.1% - 99.8%). These results suggest the great potential of the test, however, due to the limited observations, CI (confidence intervals) are very wide. More accurate values require additional studies on larger samples.

Conclusions: HBME-1 can serve as an immunocytochemical marker for differentiating benign and malignant thyroid nodules. Its use will help reduce the number of unnecessary surgeries for benign tumors, improving patients’ quality of life and reducing the burden on medical services.