Ki-67 and Cyclin D1 in subtypes of triple-negative breast cancer with different androgen profiles.

Abstract

E12552 Background: The purpose of the study was to analyze Ki-67 and Cyclin D1 expression in subtypes of triple negative breast cancer (TNBC) with different androgen profiles. Methods: Tissues of 60 patients with verified TNBC (T1N1M0/T2N0M0, ER-/PR-/Her2-) were studied. Immunohistochemical staining was performed with antibodies to androgen receptors (AR), CK5/6, Ki-67, Cyclin D1, and EGFR. Basal-like (BL) subtype was identified when > 25% cells were CK5/6+ and/or EGFR+ (any staining). Tumors with ≥10% positively stained cells were considered AR+. Parametric statistical methods were used. Significance of the difference between the two means was assessed by the Student's t-test. Results: BL TNBC showed significantly higher Ki-67 expression (81.9±3.1%), compared to other subtypes (70.8±3.1%), p < 0.05. A number of TNBC samples demonstrated Cyclin D1 overexpression ( > 30% stained cells) with no correlation with Ki-67 expression (r = 0.12). High Cyclin D1 levels were less common in BL TNBC (32.4% tumors), compared to other subtypes (43.5% tumors), but its average values were significantly higher (89.9±4.7% vs. 66.5±6.6%, p < 0.05). AR+ tumors were observed in 11 cases (18.3%). Levels of Ki-67 were similar in TNBC with different AR profiles. The percentage of BL tumors was similar in AR+ and AR- cancers (63.6% and 61.3%, respectively). Expression of Cyclin D1 was more frequent in AR+ TNBC (45.5%), vs. 34.7% in АR-. Average levels of Cyclin D1 were significantly higher in AR+ tumors (51.8±13.7%), vs. AR- (31.6±5.1%). Conclusions: TNBC differs in the Cyclin D1 leves; some tumors show its overexpression. Inhibition of cyclin-dependent kinases blocks the cell cycle, which may be useful in the TNBC treatment, which currently has no targets for therapy.