Diagnostic value of HMGB1 immunostaining on cell blocks from residual liquid-based gynecologic cytology specimens

Aberrant expression of high mobility group box 1 (HMGB1) is associated with tumor development and progression. The current study was conducted to evaluate the significance of HMGB1 immunostaining on cell block (CB) preparations in the diagnosis of neoplastic and preneoplastic lesions of the cervix. The CBs were prepared from 157 residual liquid-based gynecologic cytology specimens which were collected from women whose cervical lesions had been confirmed by histopathology. The expression of HMGB1 and p16INK4A (p16) was visualized by immunocytochemistry on the CB preparations, and the association of their expression patterns was correlated with the severity of cervical lesions. HeLa cells were used as positive control. HMGB1 expression was observed in dysplastic and neoplastic cells and increased along with the progression of cervical neoplasia. The rates of positive staining for HMGB1 in cervical intraepithelial neoplasia 1 (CIN-1), CIN-2, CIN-3, and invasive squamous cell carcinomas (ISCCs) were 69.4, 96.9, 100.0, and 100.0%, respectively. The differences between positive rates of patients with chronic cervicitis and various CINs as well as ISCCs were significant (P < 0.005). The differences in positive staining rates between each two CIN groups, and differences between CIN-1/2 and ISCCs, were also significant (P < 0.005). The expression pattern of HMGB1 was generally correlated with that of p16 (P < 0.001). HMGB1 staining was observed in some p16-negative specimens. HMGB1 immunostaining on a CB from gynecologic cytology specimens is potentially valuable for the screening of cervical lesions in cases with questionable cytology.