Which mistletoe species is used as adjunctive cancer therapy and has immunomodulatory, hypotensive, and antitumor actions?

• A. Viscum flavescens
• B. Vinca major
• C. Vitex agnus-castus
• D. Viscum album

Answer: (D)

European mistletoe, Viscum album, is used as adjunctive cancer therapy because its extracts contain mistletoe lectins and viscotoxins that modulate the immune system and also have direct anti-tumor effects. These lectins boost immune activity—enhancing natural killer cell function and macrophage responses and promoting cytokine production—while the extracts can induce tumor cell apoptosis and slow tumor growth. Some formulations may also contribute to mild blood pressure effects through vascular interactions, contributing to overall symptomatic support. This combination of immune modulation plus direct anti-tumor activity is why Viscum album is the mistletoe species most commonly associated with this use. The other options do not fit this profile: one is a different plant used for chemotherapy alkaloids, another for hormonal symptoms, and the remaining is a mistletoe species not as widely utilized for adjunctive cancer therapy.