P53 plays a key role in protecting the human genome from DNA-related mutations; however, it is one of the most frequently mutated genes in cancer. The P53 family members p63 and p73 were also shown to play important roles in cancer development and progression. Currently, there are various organic molecules from different structural classes of compounds that could reactivate the function of wild-type p53, degrade or inhibit mutant p53, etc. It was shown that: (1) the function of the wild-type p53 protein was dependent on the presence of Zn atoms, and (2) Zn supplementation restored the altered conformation of the mutant p53 protein. This prompted us to question whether the dependence of p53 on Zn and other metals might be used as a cancer vulnerability. This review article focuses on the role of different metals in the structure and function of p53, as well as discusses the effects of metal complexes based on Zn, Cu, Fe, Ru, Au, Ag, Pd, Pt, Ir, V, Mo, Bi and Sn on the p53 protein and p53-associated signaling.

Pregnancy-associated plasma protein A (PAPPA) is a metalloproteinase that regulates insulin-like growth factor availability via cleavage of IGF-binding proteins, yet its role in cancer remains incompletely understood. Using integrated public datasets, we systematically examined PAPPA expression, prognostic relevance, cellular localization, and stromal associations across multiple tumor types. PAPPA was reduced in several cancers and primarily localized to stromal cells, whereas in cholangiocarcinoma and thyroid carcinoma it was elevated and also detected in malignant cells. High PAPPA expression was associated with poorer overall survival in bladder, cervical, lung squamous, mesothelioma, pancreatic, and gastric cancers, but exhibited a protective effect in lower-grade glioma. In tumors with adverse prognosis, PAPPA strongly correlated with cancer-associated fibroblast (CAF) infiltration and CAF marker genes; however, multivariable Cox analyses indicated that PAPPA generally retained an independent prognostic factor, whereas CAF infiltration was mostly not independently associated with overall survival. Interestingly, in LGG, despite negative PAPPA–CAF correlations, multivariable analysis showed that PAPPA remained protective while CAF infiltration was associated with worse survival. Pathway analyses linked PAPPA-associated genes to proteoglycans in cancer and PI3K–AKT and RAS signaling. Collectively, these findings establish PAPPA as an independent prognostic factor across most cancers, while its expression frequently coincides with high CAF infiltration in select tumor types, highlighting the need for further investigation.