Background:
The incidence of colorectal cancer (CRC) is increasing in many low- and middle-income countries (LMICs), partly driven by demographic transitions and lifestyle changes. Cancer is increasingly recognized as a major public health challenge in these settings, where access to early diagnosis, predictive biomarkers, and innovative treatments remains uneven. Microsatellite instability (MSI)/Mismatch repair deficiency (dMMR) are key predictive biomarkers in CRC, guiding access to immune checkpoint inhibitors and personalized treatment strategies. International guidelines recommend universal MSI/dMMR screening in all newly diagnosed CRC. However, access to reference molecular testing and, consequently, to immunotherapy remains limited in many LMICs due to shortages of pathology expertise, limited molecular biology infrastructure, and financial constraints. Strengthening local diagnostic capacities while ensuring quality, equity, and sustainability is therefore a major public health priority, fully aligned with global cancer control initiatives.

Objectives:
To develop and pilot an international tele-expertise network integrating local molecular biology, AI-assisted digital pathology, multidisciplinary clinical collaboration, and capacity-building to improve access to MSI/dMMR diagnosis for colorectal cancer patients in LMICs.

Methods:
This pilot implementation project is based on a collaborative network involving an expert cancer center, global cancer control organizations, and public hospital partners in LMICs. Formalin-fixed paraffin-embedded CRC samples are processed locally according to standardized protocols. Immunohistochemistry and molecular testing for MSI/dMMR are progressively implemented and performed locally as reference methods, with active involvement of local molecular biology laboratories.
The implementation strategy is developed in close collaboration with the Fondation Mérieux, a public-interest, non-profit organization with longstanding involvement in global health and laboratory capacity-building, supporting local implementation, quality systems, and sustainability in LMIC settings.
In parallel, hematoxylin–eosin slides are digitized and securely transferred for centralized AI-assisted analysis, used as a decision-support and prioritization tool. Tele-expertise supports quality assurance, training, and multidisciplinary case discussions. Coordination across pathology, molecular biology, and oncology ensures diagnostic accuracy and appropriate integration of MSI/dMMR results into patient management, in line with international treatment guidelines.

Results:
Preliminary results include the establishment of an international telepathology workflow, engagement of partner pathology and molecular biology laboratories in LMICs, and initial assessments of local MSI testing capacities. Stepwise implementation of integrated diagnostic workflows has been initiated, supported by tele-expertise, training activities, multidisciplinary collaboration, and AI-assisted prioritization to optimize the use of reference molecular techniques in resource-limited settings.

Conclusions / Implications:
Combining local molecular biology, tele-expertise, and AI-assisted digital pathology represents a feasible and scalable approach to improve access to predictive biomarkers in colorectal cancer in LMICs. By reinforcing local diagnostic autonomy while ensuring quality and equity, this implementation initiative supports the integration of precision medicine into routine cancer care and may facilitate more equitable access to innovative cancer therapies, including immunotherapy when available, through sustainable academic–public–non-profit partnerships. This approach illustrates how technological, clinical, and organizational innovation can be translated into sustainable public health action and contribute to global cancer control efforts.