Author(s)

Yoshio Mizuno, Tsuneo Natori, Naoko Takeda, Junichi Yamada, Hiroaki Abe, Yuko Inoue, Hiroshi Seto, Kazuhiko Sato

Clinical Testing Business, Testing Division, Special Reference Laboratories, Inc., Tokyo, Japan.
Department of Breast Oncology, Tokyo-West Tokushukai Hospital, Tokyo, Japan.
Department of Clinical Pathology, Tokyo-West Tokushukai Hospital, Tokyo, Japan.
Inoue Ladies Clinic, Tokyo, Japan.
Seto Hospital, Saitama, Japan.

Purpose: The aim of this study was to assess the reliability of Ki-67 expression on core needle biopsy (CNB) and the surgical specimens of invasive breast cancer. We examined the concordance rate of Ki-67 expressions, hormone receptors, and human epidermal growth factor receptor 2 (HER2) status from a CNB with from a surgery in invasive breast cancer. Methods: A retrospective study was conducted on a clinical database of patients who underwent surgery for early breast cancer. Of these, 193 patients who underwent CNB before the surgery were enrolled. A cut-off value of 20% was used for Ki-67-positive criteria. Expression of estrogen receptor (ER), progesterone receptor (PgR), and HER2 were examined and compared with that of Ki-67. To evaluate discordance between the pathologists’ earlier assessments, we re-examined Ki-67 expression among the Ki-67 discordant group in a central laboratory. Results: The concordance rate for Ki-67 expression between the two specimen types was 77.7%, which was significantly lower than that for ER, PgR, and HER2 expression (95.9%, 88.1%, and 91.6%, respectively). The concordance rate for re-examined Ki-67 expression among the Ki-67 discordant group improved to 93.8% and was not significantly different from that for the other receptors. Conclusion: The concordance rate for Ki-67 expression between biopsy and surgical specimens was significantly lower than that for ER, PgR, and HER2 expressions, but re-examination of Ki-67 expression in a central laboratory revealed no significant difference among the receptors, suggesting the need for standard pathological assessment of Ki-67 expression for clinical use as a predictive marker of breast cancer.

Ki-67; CNB; Concordance Rate; Standard Assessment

Y. Mizuno, T. Natori, N. Takeda, J. Yamada, H. Abe, Y. Inoue, H. Seto and K. Sato, "The Reliability of Assessment of Ki-67 Expression on Core Needle Biopsy and the Surgical Specimens of Invasive Breast Cancer: Comparison of Local Pathologists’ Assessment and Central Review," Journal of Cancer Therapy, Vol. 3 No. 5A, 2012, pp. 841-845. doi: 10.4236/jct.2012.325107.