CD30 expression (ExpCD30) has been increasingly explored as a potential prognostic and therapeutic biomarker in non-Hodgkin lymphomas (NHL), particularly in diffuse large B-cell lymphoma (DLBCL) and primary mediastinal B-cell lymphoma (PMBCL).

We investigated the frequency of ExpCD30 and its association with National Comprehensive Cancer Network International Prognostic Index (NCCN-IPI), and cell of origin (Germinal Center [GC] vs. non-Germinal Center [NGC]), as well as its impact on survival in patients with DLBCL and PMBCL.

This was a retrospective observational cohort study, approved by the Ethics Committee, which evaluated cases of DLBCL and PMBCL diagnosed between 2009 and 2016 at the Cancer Institute of the State of São Paulo. Adult patients eligible for curative treatment with viable histopathological material were included. CD30+ cases were tested for EBV by in situ hybridization, and EBV+ cases were excluded. ExpCD30 was analyzed as both a continuous and categorical variable. The classification into GC and NGC subgroups followed the Hans algorithm. The association between ExpCD30 and categorical variables, such as type of biopsy tissue, NCCN-IPI risk factors, and cell of origin, was assessed using the Chi-square. The primary outcomes were progression-free survival (PFS) and overall survival (OS), estimated using the Kaplan-Meier method. Statistical analyses included univariate and multivariate Cox regression, assessment of multicollinearity, and validation of the proportional hazards assumptions. ExpCD30 was retained in the final models regardless of p-value. A significance level of p < 0.05 was adopted.

A total of 301 patients were included—279 with DLBCL and 22 with PMBCL. The overall frequency of CD30 positivity was 19.6%, with 19% in DLBCL and 27.3% in PMBCL. Among CD30+ cases, nodal biopsies were significantly more frequent (62.7%) than extranodal (37.3%), compared to 47.5% and 52.5% respectively in CD30- negative cases (p = 0.036). No significant associations were observed between ExpCD30 and NCCN-IPI risk category, or between ExpCD30 and cell of origin. ExpCD30 was not significantly associated with OS (p = 0.22) or PFS (p = 0.42). In multivariate models, the only independent predictor of worse outcomes was the presence of ≥ 4 NCCN-IPI risk factors, associated with poorer OS (HR 3.15, 95% CI: 1.99–5.01, p < 0.001) and PFS (HR 2.90, 95% CI: 1.90–4.42, p < 0.001). In the DLBCL subgroup, ExpCD30 was not significantly associated with GC vs. non-GC classification such as NCCN-IPI score. ExpCD30 did not impact OS (p = 0.35) or PFS (p = 0.70). Once again, having ≥ 4 NCCN- IPI risk factors remained the only significant prognostic factor in the multivariate analysis. Due to the small number of cases (n = 22), we were unable to conduct detailed statistical analyses in the PMBCL subgroup.

Our cohort represents the third largest sample among previously published studies and is the first in Brazil and Latin America to evaluate CD30 expression in these specific lymphoma subtypes. Our findings are consistent with most of the studies published in the international literature. CD30 positivity was observed in approximately one-fifth of cases, more frequently in nodal biopsies, but showed no significant association with major prognostic factors or survival outcomes.