CD82, also known as KAI-1, structurally belongs to tetraspanin family while categorised as metastasis suppressor gene on functional grounds. KAI1/CD82 is localized on cell membrane and form interactions with other tetraspanins, integrins and chemokines which are respectively responsible for cell migration, adhesion and signalling. In recent years apart from its significant involvement in the suppression of secondary tumours it has also been observed that KAI1/CD82 plays a vital role in virus binding and its entry inside the cell. Decreased expression of KAI1/CD82 molecule results in aggravating cancer progression. Altered expression levels of KAI1/CD82 molecule in different types of human cancer have been implicated as having prognostic value and linking to the long term survival of the patients. Increased level of KAI1/CD82 also results in the suppression of secondary tumour growth. Increased expression of this molecule results in reduced cell invasion and cell migration due to endocytosis of epidermal growth factor receptors (EGFR). Thus, KAI-1/CD82 is a pivotal molecule in the regulation of cancer cells' behaviour and has important clinical and therapeutic implications in cancer.