Toxic mechanisms of cadmium and exposure as a risk factor for oral and gastrointestinal carcinomas

Incidence and mortality rates of gastrointestinal (GI) and oral cancers are among the highest in the world, compared to other cancers. GI cancers include esophageal, gastric, colon, rectal, liver, and pancreatic cancers, with colorectal cancer being the most common. Oral cancer, which is included in the head and neck cancers category, is one of the most important causes of death in India. Cadmium (Cd) is a toxic element affecting humans and the environment, which has both natural and anthropogenic sources. Generally, water, soil, air, and food supplies are reported as some sources of Cd. It accumulates in organs, particularly in the kidneys and liver. Exposure to cadmium is associated with different types of health risks such as kidney dysfunction, cardiovascular disease, reproductive dysfunction, diabetes, cerebral infarction, and neurotoxic effects (Parkinson's disease (PD) and Alzheimer's disease (AD)). Exposure to Cd is also associated with various cancers, including lung, kidney, liver, stomach, hematopoietic system, gynecologic and breast cancer. In the present study, we have provided and summarized the association of Cd exposure with oral and GI cancers.