TROP-2 immunohistochemistry: a highly accurate method in the differential diagnosis of papillary thyroid carcinoma.
We aimed to evaluate the diagnostic utility of the novel immunohistochemical marker TROP-2 on thyroid specimens (226 tumours and 207 controls). Whole slide immunohistochemistry was performed and scored by automated digital image analysis. Non-neoplastic thyroid, follicular adenomas, follicular carcinomas, and medullary carcinomas were negative for TROP-2 immunostaining. The majority of papillary thyroid carcinoma (PTC) specimens (94/114, 82.5%) were positive for TROP-2; however, the pattern of staining differed significantly between the histopathological variants. All papillary microcarcinomas (mPTC), PTC classic variant (PTC cv), and tall cell variant (PTC tcv) were TROP-2 positive, with mainly diffuse staining. In contrast, less than half of the PTC follicular variant specimens were positive for TROP-2, with only focal immunoreactivity. TROP-2 could identify PTC cv with 98.1% sensitivity and 97.5% specificity. ROC curve analysis found that the presence of >10% of TROP-2 positive cells in a tumour supported a diagnosis of PTC. The study of intratumoural heterogeneity showed that low-volume cytological samples of PTC cv could be adequately assessed by TROP-2 immunostaining. The TROP-2 H-score (intensity multiplied by proportion) was significantly associated with PTC variant and capsular invasion in encapsulated PTC follicular variant (p<0.001). None of the baseline (age, gender) and clinical (tumour size, nodal disease, stage) parameters were correlated with TROP-2 expression. In conclusion, TROP-2 membranous staining is a very sensitive and specific marker for PTC cv, PTC tcv, and mPTC, with high overall specificity for PTC.
Department of Pathology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand. Electronic address: andrey.bychkov@live.com.
Andrey
A
Bychkov
Department of Pathology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
Pichet
P
Sampatanukul
Department of Pathology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand; Chulalongkorn GenePRO Center, Research Affairs, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
Shanop
S
Shuangshoti
Department of Pathology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
Somboon
S
Keelawat
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000951:Antigens, Neoplasm / Q000032:analysis / Q000096:biosynthesis*; D019540:Area Under Curve; D014408:Biomarkers, Tumor / Q000032:analysis*; D002277:Carcinoma / Q000175:diagnosis*; D002291:Carcinoma, Papillary; D015815:Cell Adhesion Molecules / Q000032:analysis / Q000096:biosynthesis*; D002648:Child; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012680:Sensitivity and Specificity; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000175:diagnosis*; D055815:Young Adult
D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D015815:Cell Adhesion Molecules; C499380:TACSTD2 protein, human
TROP-2; automated image analysis; differential diagnosis; immunohistochemistry; papillary thyroid carcinoma; thyroid