Atossa (Ancient Greek: Ἄτοσσα, from Old Persian *Utauθa, in Avestan: Hutaosā) was an Achaemenid queen and daughter of Cyrus the Great and Cassandane. She lived from 550 BC to 475 BC and probably was a sister of the Persian king Cambyses II.
Herodotus records in The Histories that Atossa was troubled by a bleeding lump in her breast. She wrapped herself in sheets and sought a self-imposed quarantine. Ultimately, a Greek slave, Democedes, persuaded her to allow him to excise the tumor. 
Xerxes I was the eldest son of Atossa and Darius. Atossa lived to see Xerxes invade Greece. Being a direct descendent of Cyrus the Great, Atossa had a great authority within Achamenian royal house and court. Atossa's special position enabled Xerxes, who was not the eldest son of Darius, to succeed his father.
In his history of cancer, The Emperor of All Maladies, Siddhartha Mukherjee imagines Atossa traveling through time, encountering different diagnoses and treatments for her breast cancer. Atossa becomes emblematic of cancer sufferers through history.
- Schmitt, Rüdiger (1989). "Atossa". Encyclopaedia Iranica. vol. 3. Encyclopaedia Iranica Foundation. ISBN 0-7100-9121-4.
- Mukherjee, The Emperor of All Maladies, p.41. See Herodotus, The Histories, OUP, 1998, pt. VIII
- Mukherjee, The Emperor of All Maladies, pp. 463–467