Immunophenotypic expression profile of multiple myeloma cases at a tertiary hospital in Nairobi, Kenya
Date of Award
Master of Medicine (MMed)
Dr. Anne Mwirigi
Dr. Riyat Malkit
Prof. El-Nasir Lalani
Pathology (East Africa)
Background; Multiple myeloma (MM) is a heterogeneous disease with variable patient outcomes ranging from indolent to aggressive disease. GLOBOCAN data places Kenya amongst the top five African countries for MM incidence and MM-related mortality. Aberrant expression of CD56, CD117, Cyclin D1 and Ki-67 on neoplastic plasma cells has been demonstrated to be useful in disease prognostication. However, majority of the data on MM comes from western countries. The significance of expression of this markers is uncertain in our population. The aim of this study was to determine the immunophenotypic expression profile of CD56, CD117, Cyclin D1 and Ki-67 in a cohort of patients diagnosed with MM at AKUHN.
Methods; This was a retrospective, laboratory-based cross-sectional study carried out at the Aga Khan University Hospital, Nairobi. The study population included all MM cases with available trephine blocks archived between 1st of January 2009 and 31st of March 2020. Trephine biopsies were analyzed for marker expression using immunohistochemistry. The biomarkers were described using frequencies based on the positive and negative results. Determination of association between the immunophenotypic markers and categorical variables was determined using Fischer’s exact test.
Results; A total of 83 cases were included in the study. The frequency of Cyclin D1, CD56, CD117 and K-67 expression was 28.9%(CI 0.191-0.387), 34.9%(CI 0.246-0.452), 7.2%(CI 0.017-0.128) and 50.6%(CI 0.398-0.614) respectively. Cyclin D1 positivity was significantly associated with hypercalcemia (p=0.042). Absence of CD117 expression was also noted to be associated with adverse risk parameters including an IgA isotype or light chain disease, ISS stage III disease, an abnormal baseline sFLC and a high plasma cell burden.
Conclusion; Cyclin D1 expression was congruent with previously reported studies. The frequency of CD56 and CD117 expression was lower than previously reported. This may be due to differences in disease biology between the study populations. Approximately half of cases were Ki-67 positive. Our data showed limited associations between the expression of studied markers and clinicopathologic variables and treatment response. However, this could be attributed to the small study sample size. We would recommend further characterization of the disease in a larger prospective study with the inclusion of survival outcomes and cytogenetic studies.
Mengich, I. C. (2021). Immunophenotypic expression profile of multiple myeloma cases at a tertiary hospital in Nairobi, Kenya (Unpublished master's dissertation). Aga Khan University, East Africa.