HPG80 as a broad-spectrum cancer biomarker among newly diagnosed patients at Uganda Cancer Institute: An Exploratory Cross-sectional Study

Background In low- and middle-income countries (LMICs) such as Uganda, delayed cancer diagnosis due to limited access to diagnostic tools contributes to poor outcomes. Traditional tumour markers, such as CA15-3, CA125, CEA, and PSA, are widely used but have limited sensitivity and specificity across various cancer types. Circulating progastrin (hPG80) has emerged as a potential broad-spectrum biomarker detectable in the plasma of cancer patients. This study provides initial evidence on hPG80 positivity across different cancer types among newly diagnosed patients at the Uganda Cancer Institute (UCI) and compares it with conventional tumour markers. Methods We conducted a cross-sectional study among 210 newly diagnosed, treatment-naive adult cancer patients with histologically confirmed solid tumours at the Uganda Cancer Institute (UCI). Prior to treatment initiation, venous blood samples were collected and analysed for hPG80 using the DxPG80.lab ELISA kit. Concurrently, conventional tumour markers (e.g., CA15-3, CA125, CEA, PSA, CA19-9, AFP, LDH) were measured using the Roche COBAS 6000 analyser. hPG80 positivity was defined as plasma concentrations > 3.3 pM. We compared the proportion of patients testing positive for hPG80 versus traditional markers by cancer type. Spearman’s rank correlation was used to assess relationships between hPG80 and conventional markers. Results hPG80 was positive (> 3.3 pM) in 77.1% of all participants. The most frequent hPG80 positivity was seen in oesophageal (83%), cervical (79%), breast (72%), and prostate (77%) cancers, which are among the most diagnosed cancers in Uganda. In each of these cancers, hPG80 identified more patients than the corresponding conventional tumour markers (p < 0.001), except in prostate cancer, where it performed similarly to PSA (77% vs. 80%). Although high hPG80 positivity was also noted in pancreatic and colon cancers, the small number of cases in these groups limits interpretation. No significant correlations were observed between hPG80 and conventional tumour markers, suggesting that hPG80 may reflect different biological processes. Conclusion hPG80 was detectable in a high proportion of newly diagnosed cancer patients and showed higher positivity rates than conventional markers in several common cancers in Uganda. These findings support further evaluation of hPG80 as a complementary biomarker, with potential utility in cancer detection strategies in resource-limited settings.