Tumour Immune and Ki-67 Scoring Methods as Prognostic Biomarkers in Diffuse Large B-cell Lymphoma and Aggressive B-cell Lymphomas

Tumour Immune "Hotness" and Ki-67 Scoring Methods as Prognostic Biomarkers in Diffuse Large B-cell Lymphoma and Aggressive B-cell Lymphomas: An Immunohistochemical Study

Diffuse large B-cell lymphoma (DLBCL) is the most common aggressive non-Hodgkin lymphoma with heterogeneity in its clinical presentations, biological behaviour and response to therapy (1-4). Nevertheless, despite R-CHOP chemotherapy being successful, a high percentage of patients relapsed early or were primary refractory, highlighting the urgent need for more accurate prognostic biomarkers (2,5).

With the emergence of new discoveries in cancer immunology, the focus has shifted to the tumour microenvironment (TME). The density and presence of tumour-infiltrating lymphocytes (TILs), especially CD3+ T cells and CD8+ cytotoxic T lymphocytes, are key determinants of the anti-tumour immune response (6-8). Now tumours are classified by their immune 'hotness'. 'Hot' tumours, with high T-cell infiltration, are associated with a better prognosis, whereas 'cold' tumours, with immune exclusion or desertion, are associated with a poorer prognosis (9-10).

On the other hand, the Ki-67 proliferation index is still the gold standard marker to measure the growth fraction of neoplastic cells (11). However, the optimal scoring method is yet to be established (12-13). Prognostic information may be obtained by global scoring (i.e. the proliferation index averaged over the whole tumour) and hotspot scoring (i.e. the area of maximum proliferation) (14-15).

In aggressive lymphomas the hotspot index could be a better representation of the highly proliferative clones that drive clinical progression (16-17). The present study was done to assess the combined effect of immune infiltration (CD3/CD8) and proliferation (Ki-67) to build a more accurate prognostic model for patients with DLBCL and other aggressive B-cell lymphomas treated

Inclusion Criteria:

• • Patients diagnosed with Diffuse Large B Cell Lymphoma, not otherwise specified (DLBCL, NOS) and other aggressive large B-cell lymphomas, according to current WHO/ICC diagnostic principles.

  • Histopathological diagnosis obtained by excisional biopsy, core biopsy or adequate tissue biopsy.
  • Availability of FFPE tissue blocks with sufficient viable tumor for immunohistochemical (IHC) staining.
  • Diagnostic tissue obtained before the initiation of definitive systemic therapy.
  • Available minimum clinical data: age, sex, date of diagnosis, treatment status, and follow-up/survival status.
  • For survival analysis: cases with documented follow-up date or date of death/progression.

Exclusion Criteria:

• • Inadequate tissue, exhausted block or severe fixation/processing artifact preventing reliable IHC interpretation.

  • Extensive necrosis, crush artifact or decalcification artifact in the only available diagnostic tissue.
  • Relapse biopsy after chemotherapy without available pretreatment diagnostic tissue.
  • Primary Hodgkin lymphoma, indolent B-cell lymphoma without transformation, T-cell lymphoma or metastatic non-lymphoid malignancy.
  • Cases lacking essential clinical outcome data for prognostic analysis (except for descriptive staining analysis).
  • HIV-associated, post-transplant or primary CNS DLBCL may be excluded or analyzed separately due to distinct biology.