This cross-sectional study investigates the relationship between serum IGF-1 and IGF-1Ec (E-peptide/MGF) levels and tumor burden in patients with solid tumors. By analyzing serum samples using ELISA and correlating them with clinical data such as tumor stage, size, metastasis, and lymph node involvement, the study aims to explore whether these biomarkers-particularly IGF-1Ec and the IGF-1Ec/IGF-1 ratio-can reflect tumor progression and serve as potential prognostic indicators.

Background: Insulin-like Growth Factor-1 (IGF-1) and its splice variant IGF-1Ec (also known as Mechano Growth Factor, MGF) play critical roles in cell proliferation, survival, and tumor progression. Recent evidence suggests that IGF-1Ec may act independently of the classical IGF-1 receptor pathway and contribute to aggressive tumor behavior. However, data on serum IGF-1Ec levels and their correlation with clinical tumor burden remain limited.

Objective: This cross-sectional analytical study aims to quantify serum IGF-1 and IGF-1Ec levels in patients with solid tumors and investigate their association with tumor burden parameters such as clinical stage, tumor size, lymph node involvement, and metastasis. The IGF-1Ec/IGF-1 ratio will also be evaluated as a potential prognostic biomarker.

Methods: Serum samples will be collected from approximately 60 patients diagnosed with solid tumors. IGF-1 and IGF-1Ec levels will be measured using validated ELISA kits. Clinical tumor burden will be assessed from medical records (TNM staging, metastasis, tumor diameter). Statistical analysis will include group comparisons and correlation tests.

Inclusion Criteria:

• Age ≥ 18 years
• Histologically confirmed diagnosis of a solid tumor
• Clinically stable condition, prior to chemotherapy or during standard follow-up
• Ability to provide informed consent

Exclusion Criteria:

• Hematological malignancies (e.g., leukemia, lymphoma)
• Acute or chronic liver or kidney failure
• Current use (within 1 month) of corticosteroids, growth hormone, or medications affecting IGF-1 levels
• Pregnancy or lactation
• Coagulopathy or severe anemia preventing safe venipuncture

The study will include approximately 100 adult patients (≥18 years old) diagnosed with histologically confirmed solid tumors. All participants will be recruited from the Çanakkale Onsekiz Mart University Oncology Outpatient Clinic or Inpatient Services. Only clinically stable patients will be included.