Correlation between tumor invasion and somatostatin receptor subtypes in acromegaly

Area of Science:

• Endocrinology
• Oncology
• Molecular Biology

Background:

• Somatostatin receptor (SSTR) subtype expression in somatotropinomas influences treatment response to somatostatin analogs (SSAs).
• The relationship between SSTRs and tumor invasiveness in somatotropinomas remains unclear.
• Tumor invasiveness may impact the efficacy of SSA therapy.

Purpose of the Study:

• To investigate the correlation between SSTR subtypes and tumor invasion in somatotropinomas.
• To examine the association between tumor invasiveness and the pharmacological response to SSAs.
• To identify potential biomarkers for managing somatotropinomas.

Main Methods:

• Retrospective analysis of 102 acromegaly patients undergoing surgery.
• Classification of tumors into noninvasive (Knosp grades 0-2) and invasive (Knosp grades 3-4) groups.
• Assessment of SSTR expression (SSTR1-3, SSTR5) and response to SSAs (IGF-1, GH levels, tumor volume reduction).
• Receiver operating characteristic (ROC) curve analysis for SSTR2 and tumor invasion.

Main Results:

• Invasive tumors were larger and showed significantly lower SSTR2 expression compared to noninvasive tumors (p < 0.001).
• The invasive group exhibited a poorer response to SSAs (36.4%) versus the noninvasive group (91.7%) (p < 0.001).
• Low SSTR2 mRNA levels were strongly associated with tumor invasion (AUC 0.805, p < 0.0001).

Conclusions:

• Tumor invasion in somatotropinomas is negatively correlated with SSTR2 expression.
• Lower SSTR2 levels in invasive tumors may explain the reduced response to SSA therapy.
• SSTR2 serves as a potential biomarker for managing postoperative residual somatotropinomas.