Ki67 is a commonly used marker of cancer cell proliferation, and has significant prognostic value in breast cancer. In spite of its clinical importance, assessment of Ki67 remains a challenge, as current manual scoring methods have high inter- and intra-user variability. A major reason for this variability is selection bias, in that different observers will score different regions of the same tumor.
The Ki67 antigen, which encodes two protein isoforms with molecular weights of and kDa, was originally identified by Scholzer and Gerdes in the early s 1. It is present during all active phases of the cell cycle G1, S, G2 and Mbut is absent in resting cells G0 23. In later phases of mitosis during anaphase and telophasea sharp decrease in Ki67 levels occurs 4.
Study record managers: refer to the Data Element Definitions if submitting registration or results information. Gene expression studies have identified five molecularly distinct subtypes of breast cancer that have prognostic value across multiple treatment settings including tow biologically distinct estrogen receptor ER -positive subtypes of breast cancer: luminal A and luminal B. The expression of ER-associated genes characterizes the luminal breast cancers, with luminal B tumors having poorer outcomes than luminal tumors.
The pathological complete response pCR after neoadjuvant chemotherapy is a surrogate marker for a favorable prognosis in breast cancer patients. Factors capable of predicting a pCR, such as the proliferation marker Ki67, may therefore help improve our understanding of the drug response and its effect on the prognosis. This study investigated the predictive and prognostic value of Ki67 in patients with invasive breast cancer receiving neoadjuvant treatment for breast cancer. Ki67 was stained routinely from core biopsies in patients directly after the fixation and embedding process.
Disclosures of potential conflicts of interest may be found at the end of this article. In patients with luminal subtype, pCR seems less important for outcome prediction. Ki67 decrease significantly correlated with better DFS and OS compared with no decrease, particularly in the luminal B subgroup.
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Controversy exists for the use of Ki67 protein expression as a predictive marker to select patients who do or do not derive benefit from adjuvant endocrine therapy. Mitotic count, Ki67 and Cyclin D1 protein expression were centrally assessed by immunohistochemistry on tissue microarrays. Multivariate Cox proportional hazard models including interaction between marker and treatment were used to test the predictive value of these markers.
By Caroline Helwick February 25, Advertisement. However, the study did show that tumor Ki67 levels after 2 weeks of perioperative aromatase inhibitor therapy are prognostic for outcomes and could guide the need for additional adjuvant treatment. Robertson said. The primary endpoint was time to recurrence to locoregional or distant recurrence or breast cancer death.
The proliferation marker Ki is one of the most controversially discussed parameters for treatment decisions in breast cancer patients. The purpose of this study was to evaluate the routine use and value of Ki as a prognostic marker, and to analyze the associations between Ki and common histopathological parameters in the routine clinical setting. Data from the clinical cancer registry Regensburg Bavaria, Germany were analyzed. Within the total data pool of 4, female patients, who had been diagnosed between andin 3, cases Ki was routinely determined.