Familial Non-Hereditary Gastric Cancer: Diagnosis, Management, Molecular Characteristics and Future Perspective.

Background/objectives: Gastric cancer (GC) remains a leading cause of cancer mortality worldwide. While most cases are sporadic, approximately 10% show familial clustering with only a minority explained by known hereditary syndromes. The remaining, termed familial non-hereditary gastric cancer (FNHGC), lack a defined high-penetrance germline mutation. This review aims to summarize current knowledge regarding the diagnosis, risk factors, molecular characteristics and management of FNHGC.

Methods: A comprehensive narrative review of the literature was conducted focusing on epidemiologic, molecular and clinical studies addressing families with multiple GC cases but no identified germline mutation.

Results: The etiology of FNHGC is multifactorial, and H. pylori, with its related chronic gastritis, is probably the key driver. Familial clustering likely occurs when combined with other elements such as genetic polymorphisms, shared exposures to risk factors or even epigenetic phenomena. Molecular profiling reveals distinct patterns in familial tumors such as more frequent microsatellite instability; somatic CDH1 promoter hypermethylation; and recurrent somatic mutations in TP53, RHOA and DNA repair genes. Current management focuses on genetic testing to rule out hereditary syndromes, endoscopic surveillance and mitigation of risk factors, with eradication of H. pylori paramount.

Conclusions: FNHGC represents a distinct subgroup of GC characterized by a multifactorial etiology related to exposure to risk factors and genetic susceptibility although significant gaps remain in fully explaining the condition. Ongoing research holds promise to provide tools for better detection and prevention in order to reduce the burden of GC in familial settings.