KI‐67 PROLIFERATION PATTERNS ARE PREDICTIVE OF EARLY PROGRESSION AND INFERIOR OUTCOMES IN GRADE 1–2 FOLLICULAR LYMPHOMA

Background: Follicular lymphoma (FL) is the most prevalent indolent B-cell non-Hodgkin (B-NHL). Progression of disease within 24 months (POD24) and transformation to large (LBCL) are known adverse outcomes in grade 1–2 FL. There a need develop practical sensitive biomarkers risk-stratify these patients (pts) at diagnosis. Ki-67 staining widely available biomarker without defined role FL, however has potential better highlight tumor microenvironment (TME) based on its colocalization with subsets T-cells. We thus set out characterize high-risk pt features immuno-architectural patterns FL Methods: Diagnostic biopsy slides from 68 pts concurrent LBCL treated University Chicago were collected 11/2001 2/2021. Grade histology was confirmed by H&E-stained slides, stained scored for including peripheral follicular pattern Ki-67% (pKI), central/diffuse (cKI), extrafollicular (eKi). Outcomes assessed overall survival (OS), occurrence POD24 time initial treatment, LBCL. compared log-rank Mann-Whitney tests significance. Results: Median age diagnosis 61 years (yrs) (IQR 52–69 yrs), 57% male. Eleven (16%) experienced first 17 (25%) subsequently transformed follow-up 9.0 yrs 6.1–11.7 yrs). pKi 20% 11%–40%) versus 3% 0%–15%) those (p = 0.01). cKi 9%–30%) 5% 2%–15%) 0.02). eKi 4%–6%) 1%–3%) 0.04). no association between pKi, cKi, or Pts pKI ≥ 10% also had significantly inferior 5-yr OS 85% (95% CI: 73%–99%) 100% < 0.01) (Figure 1A). A cKI score not associated 1B). Keywords: diagnostic prognostic biomarkers, lymphoma, pathology classification lymphomas Conflicts interests pertinent abstract G. Venkataraman Consultant advisory EUSA Pharma Honoraria: ASH J. P. Kline Janssen, Sanofi, COTA Healthcare Kite Inc./Gilead Research funding: Merck, Inc./Gilead, Seattle Genetics, Verastem Oncology A. Riedell Abbvie, Genmab, ADC Therapeutics, Pharmacyclics, Novartis, BMS, Kite/Gilead, Nurix Nektar Takeda, Intellia Sana Biotechnology, BeiGene, CVS Caremark MorphoSys, CRISPR Calibr, Xencor, Fate Tessa Therapeutics M. R. Bishop Celgene, Novartis Incyte, Agios, Celgene Other remuneration: