Serum Zinc, Copper, and Lead Levels in Iraqi Gastric Cancer Patients: A Gender-Stratified Case-Control Study with ROC Diagnostic Analysis.

Trace element imbalances are implicated in cancer pathophysiology, yet data from Iraq, a country with distinct environmental and industrial exposures, remain scarce. The stomach plays a central role in trace element absorption through its acidic environment and digestive processes, and gastric cancer disrupts this function, potentially altering systemic trace element homeostasis. This study measured serum zinc (Zn), copper (Cu), and lead (Pb) concentrations in gastric cancer patients and evaluated their diagnostic potential with gender-stratified analysis. A case-control study was conducted in Najaf, Iraq (2022-2024), enrolling 100 gastric cancer patients and 100 age-matched healthy controls (50 males and 50 females per group). Serum Zn and Cu were quantified by flame atomic absorption spectrometry (FAAS); Pb was measured by graphite furnace AAS (GFAAS). Independent samples t-tests compared group differences, and receiver operating characteristic (ROC) analysis assessed diagnostic accuracy. Female patients showed significantly lower serum Zn (100.43 ± 64.25 vs. 818.31 ± 130.26 ppb, p < 0.001) and higher Cu (1466.87 ± 568.69 vs. 977.79 ± 249.30 ppb, p < 0.001) compared to healthy controls. Male patients showed significantly lower Cu (89.50 ± 15.50 vs. 173.14 ± 98.94 ppb, p < 0.001), while Zn did not differ significantly (p = 0.394). Serum Pb was elevated in both sexes (females: 40.31 ± 9.43 vs. 11.98 ± 2.68 ppb; males: 44.79 ± 10.33 vs. 12.38 ± 2.68 ppb; both p < 0.001). ROC analysis showed Pb to be the strongest discriminator in both sexes (AUC = 0.989), while Zn was a strong discriminator in females (AUC = 0.994) but poor in males (AUC = 0.396). Serum Pb showed consistent elevation across both sexes and strong diagnostic accuracy, suggesting its potential as a cancer-associated biomarker in this population. Gender-specific differences in Zn and Cu underscore the role of sex as a biological modifier in trace element metabolism during gastric cancer. Larger multicenter studies with comprehensive environmental and dietary data are warranted.