SSTR2 expression in EBV-positive and EBV-negative lymphomas.

BACKGROUND

Somatostatin receptor 2 (SSTR2) protein expression is aberrantly upregulated in various tumors and can be visualized using scintigraphy or radiological techniques and therapeutically targeted using octreotide-based molecules.

PURPOSE: In this study, we assessed SSTR2 expression in the largest cohort of hematopoietic proliferations examined to date and interrogated the relationship between EBV and SSTR2 in EBV-associated lymphomas as a possible mechanism for SSTR2 upregulation.

METHODS

We retrospectively identified 407 cases of lymphoma from Guatemala, a country with a high prevalence of EBV-associated lymphomas. SSTR2 protein expression was assessed by immunohistochemistry, while EBV was assessed by in situ hybridization for EBV-associated small RNAs.

RESULTS

We found SSTR2 expression in 43% (20/47) of EBV-positive classic Hodgkin lymphomas (cHL) and 0% (0/12) of EBV-negative cHL cases. All but one of the other EBV-associated lymphomas (n = 53) were negative for SSTR2. Within the EBV-negative non-Hodgkin lymphomas assessed, 33% (1/3) of diffuse large B-cell lymphoma (DLBCL)/high-grade B-cell lymphoma (HGBL) with MYC and BCL2 rearrangement, 17% (25/149) of DLBCL not otherwise specified, and 17% (5/29) of follicular lymphomas showed SSTR2 expression. All other lymphomas showed no significant SSTR2 expression.

CONCLUSIONS

Our study demonstrates that EBV infection is required, but not sufficient, to upregulate SSTR2 in classic Hodgkin lymphoma, but not in other EBV-associated lymphomas. We also provide data to suggest that SSTR2 is associated with "higher-grade" germinal center-derived B-cell lymphomas in EBV-negative non-Hodgkin lymphomas.