Mathematical modelling has been used to study tumor-immune cell interaction. Some models were proposed to examine the effect of circulating lymphocytes, natural killer cells, and CD8+T cells, but they neglected the role of CD4+T cells. Other models were constructed to study the role of CD4+T cells but did not consider the role of other immune cells. In this study, we propose a mathematical model, in the form of a system of nonlinear ordinary differential equations, that predicts the interaction between tumor cells and natural killer cells, CD4+T cells, CD8+T cells, and circulating lymphocytes with or without immunotherapy and/or chemotherapy. This system is stiff, and the Runge–Kutta method failed to solve it. Consequently, the “Adams predictor-corrector” method is used. The results reveal that the patient’s immune system can overcome small tumors; however, if the tumor is large, adoptive therapy with CD4+T cells can be an alternative to both CD8+T cell therapy and cytokines in some cases. Moreover, CD4+T cell therapy could replace chemotherapy depending upon tumor size. Even if a combination of chemotherapy and immunotherapy is necessary, using CD4+T cell therapy can better reduce the dose of the associated chemotherapy compared to using combined CD8+T cells and cytokine therapy. Stability analysis is performed for the studied patients. It has been found that all equilibrium points are unstable, and a condition for preventing tumor recurrence after treatment has been deduced. Finally, a bifurcation analysis is performed to study the effect of varying system parameters on the stability, and bifurcation points are specified. New equilibrium points are created or demolished at some bifurcation points, and stability is changed at some others. Hence, for systems turning to be stable, tumors can be eradicated without the possibility of recurrence. The proposed mathematical model provides a valuable tool for designing patients’ treatment intervention strategies.

A mathematical model has been utilized to examine the interaction between tumor cells and immune cells. In this model, the immune cells include natural killer cells, circulating lymphocytes, CD8+T cells, CD4+T cells, and cytokines. The model not only represents the traditional role of CD4+T cells in activating CD8+T cells but also illustrates its role in killing the tumor via the secretion of cytokines. Besides, treatments with both chemotherapy and immunotherapy are considered. However, since this model was not fitted to experimental data before, parameter estimation is performed to fit the model with experimental data, first. The estimation is validated to verify the correctness of the model using the experimental data for the tumor growth. Second, numerical experiments are performed using a set of human data. Results show the mutual relations between tumor cells, and body immune cells in the absence and in the presence of therapy. Results also show that CD4+T cells could play a crucial role in immunotherapy. Third, sensitivity analysis is performed by calculating the normalized sensitivity coefficients to identify the relative influence of body parameters on the tumor cell population. The obtained results provide a tool to identify which parameters should be increased or decreased before treatment to get the optimal immune response.

Medical educators are in a continuous quest to close the gap between the needs of medical practice and the rising expectations of the communities in their countries. During the past two decades, competency-based medical education has been evolving as an appealing strategy to close this gap. In 2017, the Egyptian medical education authorities mandated all medical schools to change their curricula to comply with revised national academic reference standards, which changed from outcome-based to competency-based. In parallel, they also changed the timeline of all medical programs for six years of studentship and one-year internship to five years and two years, respectively. This substantial reform involved the assessment of the existing situation, an awareness campaign for the proposed changes and an extensive national faculty development program. Monitoring the implementation of this substantial reform was performed through surveys, field visits and meetings with students, teaching staff and program directors. In addition to the expected challenges, the COVID-19-associated restrictions presented a significant further challenge during the implementation of this reform. This article presents the rationale for and steps of this reform, the challenges faced and how they were addressed.

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The COVID-19 issue forced necessary changes in medical education that have been demanding and adjusting for different medical colleges, but they also provide a great opportunity for the betterment and possible challenging and useful transformation of medical education. This chapter examined the responses of medical organizations to this pandemic, its merits, and its challenges. It analyzed the potential effects of new strategies’ recognition and application on medical education in the post-COVID-19 period. The status of medical education before COVID-19 and the challenges of adopting competencies have been reviewed. The teaching and assessment strategies innovated in the COVID-19 era and reflections from faculty and students were discussed. Over the previous years, the pandemic has questioned concepts about how medical education should be delivered. The COVID-19 pandemic offers the medical education community a unique chance to reorient itself away from outdated standards and practices and toward more societally responsible and accountable standards and practices. All involved in medical education should all work together to prevent situations from “snapping back” to how they have always been because they were accepted practices and would be lost if the pandemic had the potential to disrupt growth and reform.