GATA3 Gene - a Potential New Biomarker Associated with Adverse Outcomes in ALK1-Negative Anaplastic Large Cell Lymphoma: Preliminary Results from a Retrospective Cohort of 80 South American Cases of Nodal Peripheral T Lymphoma

Introduction: Nodal peripheral T-cell lymphomas (nPTCLs) comprise a heterogeneous group of mature and aggressive T-cell lymphoid malignancies, including peripheral T-cell lymphoma, not otherwise specified (PTCL, NOS), angioimmunoblastic T-cell lymphoma (AITL) and anaplastic large cell lymphomas (ALCL) ALK1-positive and ALK1-negative. The differential diagnosis of nPTCL can be very challenging in clinical practice and it has a markedly heterogeneous prognosis. Accurate biomarkers to distinguish the different histological subtypes of nPTCL and to stratify its prognosis are essential to improve the therapeutic approach. The aim of this study was to assess the prognostic impact of GATA3 gene expression, as well as its ability to discriminate between different histopathological subtypes of nPTCLs.

Methods: In this observational, retrospective and single-center study, we analyzed clinical-epidemiological data, outcomes and molecular characteristics of 80 nPTCL patients treated at the largest Brazilian cancer center from January 2000 to December 2017. Analysis of GATA3 gene expression was assessed by quantitative real-time polimerase chain reaction (qRT-PCR) of tumor tissue biopsies fixed in formalin and embedded in paraffin (FFPE) at the time of diagnosis. The association of relative expression of the GATA3 gene with pathological variants of nPTCL was determined by the Kruskal-Wallis test and the Dunn’s post-hoc test. The cutoff value of GATA3 expression capable of differentiating nPTCLs variants was determined by constructing receiver-operator-characteristic (ROC) curves. Overall survival (OS) and progression-free survival (PFS) curves were estimated using the Kaplan-Meier method.

Results: The clinical and epidemiological characteristics of the 80 nPTCL patients are summarized in Table 1. Median age was 49 years (IqR 34-59), 43-80 (53.7%) of patients were male. Of these, 36.3% were classified as PTCL-NOS, 31.2% as ALK-negative ALCL, 21.2% as ALK-positive ALCL and 11.3% as AITL. Most of the cases had an advanced stage (III and IV Ann Arbor). With a median follow-up of 1.72 years, the estimated OS at 2 years and PFS were 52.2% and 39.5%, respectively. The median level of GATA3 gene expression was 0.49% (range 0 - 7.07%) in the global cohort, being 0.11% for ALK-positive ALCL, 0.46% for ALK-negative ALCL, 0.86% for PTCL, NOS and 0.67% for AITL. The difference in expression of the GATA3 gene between different nPTCL variants was statistically significant (p <0.001) - Figure 1. The levels of expression of the GATA3 gene ≥ 0.71% discriminated PTCL, NOS from ALK-negative ALCL and AITL with a sensitivity of 62% and specificity of 80.3%, contributing to the differential diagnosis of these neoplasms, particularly in cases of ALK-negative ALCL versus PTCL, NOS CD30-positive. Overexpression of GATA3 ≥ median was associated with poor 2-year OS for PTCL, NOS (46.7% x 21.4%, p = 0.04) and for ALK-negative ALCL (85.7% x 54.5%, p = 0.04) - Figures 2 and 3.

Conclusion: Despite the relatively small number of patients in our cohort, preliminary results suggest that overexpression of the GATA3 gene may be an important biomarker associated with poor prognosis in PTCL, NOS and ALK-negative ALCL. Our results corroborate the findings of Iqbal et al, 2014, reinforcing the adverse prognostic impact of GATA3 gene expression in PTCL/NOS, and we show that its overexpression may be a potential novel biomarker related to poor prognosis for ALK-negative ALCL. In addition, it has been demonstrated here that GATA3 can play an auxiliary role in discriminating different subtypes of nPTCLs, aiding the differential diagnosis of these neoplasms, which often have overlapping clinical and pathological aspects. Other studies with larger series of patients should confirm our findings.