Cancer

Cancer is a mentioned condition.

Background
Cancer was categorized into Types I and II, and affected various characters:
 * Lily Bell, a former resident of Quincy, was diagnosed with cancer by Doctor Sun.
 * Randall Clark assumed that he had lung cancer.
 * Dorothea, the granddaughter of Ansel Abrahms, died from Leukemia.
 * Bennett Faust, an inhabitant of Vault 87, died from Type II cancer.
 * Dontrelle Haines states that he has cancer.
 * Olivia P. Henderson, a guard for the Responders, was diagnosed with terminal cancer shortly before the Great War.
 * Evelyn Hornwright died from cancer in 2076.
 * Brody Jones, the overseer of Vault 108, was diagnosed with a rare and terminal strain of cancer.
 * Mercia Koster, an inhabitant of Vault 87, died from Type I cancer.
 * Roger Maxson, founder of the Brotherhood of Steel, died from cancer.
 * Millicent, the wife of Gilbert Hopson, died from cancer, which according to him, she likely obtained from radiation.
 * Shaun, the leader of the Institute, is dying from cancer.
 * Winston, the dog of Bill Thomas, was diagnosed with large cell lymphoma.

Additionally, the disease is also mentioned by a number of people and sources:
 * Ella Ames mentions it in one of her terminal entries.
 * Attis states that a greater level of mutation is "like a terrible cancer."
 * Tree Father Birch uses the term in an analogy.
 * Doc Church comments that the Lone Wanderer better has cancer for bothering him.
 * An Institute scientist mentions that analyzing test samples should not take as long as curing cancer.
 * Nancy Kroydon mentioned a cancer treatment facility near Germantown in her log.
 * Arthur Maxson refers to the Institute as "cancer beneath the Commonwealth" during his address.
 * Midea comments that contaminated people suffer from "some form of cancer."
 * Steve refers to the escape of Franc and Manson as "cancer in our midst."
 * A holodisk mentions the induction of cancer into 15 chimpanzees.
 * The terminals for the Pioneer Scout exam mention cancer several times.

Appearances
Cancer is mentioned in Fallout, Fallout 2, Fallout 3 and its add-on The Pitt, the Fallout: New Vegas add-on Honest Hearts, Fallout 4, and Fallout 76.

Behind the scenes

 * Script notes for the Mariner read "{Quietly sharing raw thoughts of a cancer patient / Depressed}"
 * An unused holotape in Fallout 76 would have mentioned that eating plants does not cause cancer.
 * Cancer would have also been present in the canceled Van Buren.