ENPP1/cGAS (EG) and FAP Expression Profiles in Solid Tumors: An Immunohistochemical Study in a Vietnamese Cohort

ENPP1/cGAS (EG) and FAP Expression Profiles in Solid Tumors: An Immunohistochemical Study in a Vietnamese Cohort

This Vietnam-based observational study examines ecto-nucleotide pyrophosphatase/phosphodiesterase 1/cyclic GMP-AMP synthase (ENPP1/cGAS) protein and stromal fibroblast activation protein (FAP) expression in multiple solid tumor samples using immunohistochemistry (IHC). The study involves no investigational treatments or participant-facing procedures. Tumor samples used in this study consist exclusively of archived formalin-fixed paraffin- embedded (FFPE) tumor samples that were collected as part of routine clinical diagnosis or treatment and for which all required procedures for standard clinical care have been completed. Only archived tumor samples obtained from routine clinical care will be included in this study. No additional biopsy, surgical resection, or specimen collection will be performed for research purposes, and no sample will be diverted prior to completion of clinical requirements. All included archived tumor samples will undergo ENPP1, cGAS, and FAP IHC analysis according to the procedures specified in the Laboratory Manual.

Inclusion Criteria:

• Confirmed diagnosis: Patients with a histopathologically or cytologically confirmed diagnosis of malignant solid tumors, including but not limited to colorectal cancer (CRC), hepatocellular carcinoma (HCC), lung cancer, melanoma, pancreatic cancer,breast cancer, or other solid tumors relevant to the study objectives.

• Age: Vietnamese patients aged ≥ 18 years at the time of tumor tissue collection.

• Availability and quality of biospecimens:

  1. Availability of formalin-fixed, paraffin-embedded (FFPE) tumor tissue specimens collected within 24 months prior to specimen eligibility verification and currently stored at the study site.
  2. Tumor tissue specimens confirmed by a study pathologist to contain an adequate proportion of viable tumor cells (minimum of 1500 tumor cells per section) and sufficient material for analysis (at least one FFPE block or four unstained slides, 3-5 um in thickness).
  3. Only archived residual tissue specimens remaining after completion of all routine clinical diagnostic and/or therapeutic purposes will be used for study purposes.

• Availability of clinical data: Patient medical records must contain essential baseline information required for the study, including at minimum basic demographic data (age, sex) and histopathological diagnosis.

• Ethical considerations: The study will be conducted using tissue specimens classified as archived samples at the time of eligibility assessment and is eligible for a waiver of informed consent in accordance with the requirements and approval of the Local Ethics Committee/Institutional Review Board (LEC/IRB).

Exclusion Criteria:

• Discordance between clinical diagnosis and tissue histopathology: The diagnosis documented in the medical record is inconsistent with the histopathological findings of the tissue specimen intended for study use.
• Legal or policy restrictions: Patients or their legally authorized representatives have declined the use of tissue specimens for secondary research purposes, or the specimens are not permitted for research use under institutional policies or decisions of the LEC/IRB.