TCL-302: Immunohistochemical Characterization of Anaplastic Large Cell Lymphoma Using Tissue Microarray

Context: Anaplastic Large Cell Lymphoma (ALCL) is a type of mature T-cell lymphomas with systemic and primary cutaneous (PCALCL) subtypes. Systemic ALCL includes anaplastic lymphoma kinase (ALK)+ and ALK-. ALK+ usually has the NPM/ALK gene, which has favorable prognosis compared to ALK-. PCALCL is usually indolent. DUSP22 rearrangement in ALK-ALCL has a favorable outcome like ALK+, indicating alternate pathways of ALCL. Objective: Our primary aim was to compare protein expression levels of selected signaling molecules in oncogenic pathways of ALCL (JAK1, STAT3, DUSP22, ERB4, BLIMP1, SOCS3) among the three subtypes. We also correlated expression levels to ORR, PFS, DFS, and OS. Design: This is a retrospective study correlating protein expression levels of various antibodies across 27 patient tissue samples. Setting: The study was set at H. Lee Moffitt Cancer Center and Research Institute, an academic referral center. Patients or other participants: We identified 50 ALCL patients from 2000–2019. Twenty-seven tissue samples (6 ALK+, 10 ALK-, 8 PCALCL, 3 controls) met eligibility criteria, which included pathologist-reviewed diagnosis of ALCL subtypes (ALK+, ALK-, PCALCL) and consent to the Tissue Core database. Interventions: Replicate cores were taken and TMAs were constructed from formalin-fixed, paraffin-embedded lymph node or skin biopsies. IHC was performed with Abs to selected proteins. Stained TMA was scanned using Aperio™ ScanScope XT2 with a 200×/0.8NA objective lens at 5 min/slide via Basler tri-linear array detection. TMAs were analyzed using Aperio Nuclear V9 Default algorithm with thresholds for stain intensity: Strong = 130, Moderate = 188, Weak = 162 to determine the % positive biomarker stain within each core. Main outcome measures: The primary study outcome measurement was comparison of protein expression levels based on specific pathways known or hypothesized to be involved in ALCL pathogenesis. We hypothesized that these protein expression levels would correlate to time to event outcomes Results: PCALCL, ALK+, and ALK- subgroups demonstrated a significant difference in SOCS3 expression with mean and std respectively: 42.4% (0.153), 17.4% (0.089), and 21.0% (0.155);p=0.008. Among all pairs, ALK+ and PCALCL were statistically different (p=0.011). Patients with high BLIMP1 expression (% larger than median, 28.5%) regardless of ALCL subtype were associated with better mOS (not reached) compared to patients with low ( Conclusions: We identified a significant difference in expression of two Abs among three subtypes of ALCL. Increased BLIMP1 was associated with favorable prognosis and could potentially be a positive prognostic marker. Increased SOCS3 appears more prevalent in PCALCL than systemic ALCL, suggesting a potential utility in DDx. We plan to validate our results in a larger sample. Adding secondary markers like Bcl-2 can be used in the future to correlate expression levels and response to targeted agents, such as venetoclax. Funding: University of South Florida Graduate Medical Education Grant ($7500).