Only 29.4% of small-cell lung cancer samples expressed somatostatin receptor subtype 2, suggesting peptide receptor radionuclide therapy may benefit a limited but identifiable subset of patients.
29.4% SSTR2 expressionNearly a third of small-cell lung cancer samples expressed somatostatin receptor 2, the main target for peptide receptor radionuclide therapy
What the researchers found
SSTR1 was absent in all SCLC samples. SSTR2 was expressed in 29.4% and SSTR3 in 4.35% of cases. Co-expression of SSTR2 and SSTR3 occurred in 5.3% of patients. Female patients showed a trend toward higher expression, and older patients trended toward lower SSTR2 expression, but neither reached statistical significance. Disease stage did not correlate with receptor expression.
Why it matters
Somatostatin analogue therapy and peptide receptor radionuclide therapy (PRRT) require the tumor to express somatostatin receptors. This study shows that while not all SCLC patients are candidates, nearly a third express SSTR2 — making screening worthwhile for identifying patients who could benefit from peptide-targeted treatments.
The numbers in context
SSTR subtypes 1, 2, and 3 were analyzed using immunohistochemistry on SCLC tissue samples.
How the study worked
Tissue microarray analysis of 147 paraffin-embedded SCLC samples. Immunohistochemistry using anti-SSTR1, SSTR2, and SSTR3 antibodies, calibrated with healthy human pancreatic islets as positive controls. Slides scored by stain intensity and percentage of stained cells.
Who was studied
Tissue samples from patients with small-cell lung cancer
What this study cannot tell us
Retrospective tissue analysis without clinical outcomes data — receptor expression doesn't guarantee therapeutic response. Sample size of 147 is moderate. No predictors of expression reached statistical significance. Only three SSTR subtypes were tested; SSTR4 and SSTR5 were not assessed.
How to read the evidence
Rated preliminary: tissue expression study without clinical treatment outcomes. Establishes receptor presence but doesn't demonstrate therapeutic efficacy.
When this study was published
Published in 2024. Contributes to the growing evidence base for expanding somatostatin-targeted therapies beyond traditional neuroendocrine tumors.
The bigger picture
Peptide receptor radionuclide therapy has transformed treatment for neuroendocrine tumors. Extending this approach to SCLC could provide a new therapeutic option, but patient screening for somatostatin receptor expression is essential for identifying who would benefit.
Questions still open
- Would SSTR2-positive SCLC patients respond to peptide receptor radionuclide therapy?
- Are SSTR4 or SSTR5 expressed in SCLC and could they serve as additional targets?
- Could SSTR expression be used as a prognostic marker in SCLC?
Common questions
Can somatostatin-based therapy work for lung cancer?
What is peptide receptor radionuclide therapy?
Read the original research
Expression Analysis of SSTR 1, 2 and 3 in Small-cell Lung Cancer Patients as Targets for Future Peptide Receptor Radionuclide Therapy.
Anticancer research, 44(9), 3807-3812
Citation
Sagie, Nitzan; Romanov, Elizabeth; Kezerle, Yarden; Meirovitz, Amichay; Sheva, Kim. (2024). Expression Analysis of SSTR 1, 2 and 3 in Small-cell Lung Cancer Patients as Targets for Future Peptide Receptor Radionuclide Therapy.. Anticancer research, 44(9), 3807-3812. https://doi.org/10.21873/anticanres.17206