Unveiling the association of cancer stem cell markers with survival in follicular lymphoma patients

Background: Follicular lymphoma (FL) is the second most prevalent subtype of non-Hodgkin's lymphoma characterized by a protracted waxing and waning clinical course. Despite advances in treatments, about half of FL patients experience relapse within five years and become refractory to treatment. Clinical risk factors such as FL International Prognostic Index (FLIP) have not been used to guide the selection of treatment strategies. So far there are no prognostic markers for FL patients or physicians to select their treatment or understand their treatment resistance as well as relapse courses. Here we identified the cancer stem cell (CSC) markers in tissue microarray slides (TMA) and determined their association with FL patient survival. Methods: Total 105 FL pts with available lymph node biopsy blocks were identified by AI software Deep6 and Slicer Dicer for query building in EPIC (ICD-10 code: C82.9). Demographic and clinicopathological characteristics of these FL pts were collected. FL patients were divided in two groups: FL pts with short-term survival (less than 5 years) and long-term survival (more than 20 years). FFPE blocks from 59 FL pts lymph node biopsies were collected and used to create tissue microarray slides (TMA). H&E staining and IHC staining of FL cells (CD20) and CSCs (ABCG2, Ki67, and OCT3/4) were performed. Frequency of CSCs was analyzed using HALO® software. statistical analyses were performed using GraphPad prism 9. Two-sided p values <0.05 were considered statistically significance. Results: Among 59 FL patients, 26 (44.1%) pts were short-term survival, and 33 (55.9%) FL pts were long-term survival. Although no difference in the frequencies of CD20+ cells between the short-term and long-term survival groups, significant increases in the frequencies of single CSC markers (ABCG2, Ki67, or OCT3/4) as well as CSC combination markers (ABCG2+, Ki67+, OCT3/4+) were found in the short-term survival group compared to the long-term group (p values <0.05). Conclusion: Our results unveil phenotypically distinct CSC markers that are independence of existing prognostic markers and associated with short-term survival in FL pts, indicating their prognostic value in predicting FL patients' outcome. Evaluation of CSC markers may aid in identifying high-risk individuals and guiding personalized treatment in FL patients.