From the Guidelines
MIB-1 (Ki-67) is a crucial prognostic marker in lymphoma, particularly in mantle cell lymphoma (MCL), where a cutoff of greater than 30% is used to define high-risk disease 1.
Importance of MIB-1 in Lymphoma
MIB-1 (Ki-67) is an important prognostic marker in lymphoma that measures cellular proliferation rates. Higher MIB-1 expression generally indicates more aggressive lymphoma behavior and often correlates with poorer outcomes.
Prognostic Value in Mantle Cell Lymphoma
In the context of mantle cell lymphoma (MCL), the Ki-67 score has been prospectively validated as a powerful prognostic tool across various treatment settings 1. The combination of Ki-67 score with the mantle cell international prognostic index (MIPI) to form the "biologic MIPI" (MIPI-b) allows for better discrimination of disease risk and supports the idea that age alone should not be used to select treatment 1.
Clinical Application
The use of MIB-1 (Ki-67) in clinical practice is essential for guiding treatment decisions in lymphoma patients. Pathologists routinely include MIB-1 percentages in lymphoma diagnostic reports to help clinicians interpret the results alongside other prognostic factors, including clinical stage, LDH levels, and molecular subtypes, for comprehensive risk assessment and treatment planning 1.
Key Considerations
It is essential to standardize quantification methods and centrally review specimens to ensure accurate Ki-67 scoring, especially since poor specimen quality and variable reproducibility can limit the utility of Ki-67 staining 1.
Future Directions
Gene expression profiling (GEP) and other emerging technologies may further refine prognostic stratification and identify novel therapeutic targets in MCL, but the Ki-67 score remains a critical component of current risk assessment strategies 1.
From the Research
MIB-1 Marker and Lymphoma
- The MIB-1 labeling index is used to evaluate the proliferation of tumor cells in lymphoma 2, 3.
- A high MIB-1 labeling index is associated with poor prognosis in patients with follicular lymphoma 2.
- The MIB-1 labeling index can be used to stratify B-cell non-Hodgkin lymphoma into indolent, aggressive, and highly aggressive groups 3.
- Cutpoints for the MIB-1 labeling index have been established to separate these groups, with <38% indicating indolent lymphoma, ≥38% to ≤80.1% indicating aggressive lymphoma, and >80.1% indicating highly aggressive lymphoma 3.
MIB-1 Marker in Specific Types of Lymphoma
- In follicular lymphoma, an MIB-1 labeling index of ≥10% is associated with poor progression-free survival and overall survival 2.
- The MIB-1 labeling index can be used to predict the prognosis of patients with diffuse large B-cell lymphoma, although the optimal cutpoint for this type of lymphoma is not established 3, 4.
Treatment of Lymphoma
- Rituximab in combination with cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) is a standard treatment for diffuse large B-cell lymphoma 5, 4, 6.
- The efficacy and safety of R-CHOP have been established in several studies, with complete response rates ranging from 42.4% to 50.6% 5, 6.
- Subcutaneous rituximab has been shown to be safe and effective, with similar efficacy and safety to intravenous rituximab, and improved patient satisfaction and time savings 6.