Uterine smooth muscle tumors (USMT) are common, behavior-distinct gynecological tumors; including: leiomyoma (ULM), leiomyosarcoma (ULMS), and smooth muscle tumors of undetermined malignant potential (STUMP). Pre-operative distinction is difficult, thus diagnosis relies on histopathology. Immunohistochemistry (IHC) had been used to help in distinction. We studied two markers (stathmin-1 and CD147) to demonstrate whether they have diagnostic/ prognostic assist. Sixty seven USMT are studied. Age, follow up, and recurrence/metastasis data were collected. Representative slides were stained and Histologic score (HS) calculated as stain intensity (SI) X percentage of positive tumor cells (PP). Results were grouped as low expression (LE) and high expression (HE); then correlated to tumor types, and risk of recurrence/ metastasis. Statistical analysis (P < 0.05); Sensitivity, specificity, positive and negative predictive values and confidence intervals in diagnosing ULMS were calculated. Stathmin-1 HS (p= 0.000) and HE (p=0.002) were different among groups. Same as for CD147 HS and HE (both p=0.000), with a gradient increase from LM to STUMP to ULMS. Sensitivity, specificity, positive and negative predictive values and confidence intervals in diagnosing ULMS were as following: For stathmin-1 HS: 92 %; 20 %; 42 %; and 80 % (CI= 44-96 %). For Stathmin-1 HE: 80 %; 66 %; 60 %; and 84 % (CI=66-94 %). For CD147 HS: 85 %; 22 %; 41 %; and 69 %. For CD147 HE: 58 %; 49 %; 42 %; and 65 % (CI= 45-80 %), respectively. Recurrence / metastasis were documented in 6 cases (4 ULMS; 2 STUMP) with follow up ranging from 6 months to 102 months. 5 tumors had stathmin-1 HE (p=0.099); 2 had CD147 HE (p=0.393) in the primary tumors. STMN1 and CD147 are helpful diagnostic tests for USMT sub-typing, especially for ULMS. Gradient increase of expression from LM, to STUMP, to ULMS may indicate a role in malignant transformation in USMT, and in increased risk of recurrences/metastasis.
KEY WORDS: Leiomyoma; Leiomyosarcoma; Smooth muscle tumors of uncertain malignant potential (STUMP); Stathmin- 1; CD147.