Grateful to Benjamin Vincent and Alex Rubinsteyn for our many conversations on this topic, and comments on drafts of this essay!

Introduction

When most people hear of “cancer vaccine,” they’ll think of normal vaccines. Perhaps they’ll even think of what ostensibly is a cancer vaccine: the HPV vaccine. These vaccines—and those akin to them—are not the subject of this essay, as those are preventive vaccines against an infectious cause of cancer. When you inject one of those, you are vaccinating against a virus. The virus causes cancer. Prevent the virus, prevent the cancer. This is standard vaccinology applied to an oncogenic pathogen, and amongst the approved ones, they work decently well, but are not, in any meaningful sense, what oncologists mean when they talk about cancer vaccines.

Typical cancer vaccines are vaccines given to you when you have cancer.

These have been worked on for forty years, and have largely failed.

It's a grim field. I’ve talked with a fairly high number of biology folks at this point, and ‘cancer vaccines don’t work, right?’ is a common sentiment amongst them, even those who have never touched the area. Of course, the researchers who actually work in this specific domain [...]

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Outline:

(00:31) Introduction

(02:35) The immunological theory behind cancer vaccines

(19:38) The past and present of TAA/CTA cancer vaccines

(26:33) The upcoming era of neoantigen cancer vaccines

(37:59) The stranger approaches to cancer vaccines

(45:30) Conclusion, and what lies ahead

The original text contained 3 footnotes which were omitted from this narration.

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First published:
June 8th, 2026

Source:
https://www.lesswrong.com/posts/nWwDciCqfodBifvEP/how-to-build-a-cancer-vaccine-and-whether-they-will-work

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Narrated by TYPE III AUDIO.

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Images from the article:

Ornate Renaissance painting depicting crowned figure among dense crowd with elaborate golden decorations.

Kaplan-Meier survival curve comparing recurrence-free survival for two treatment groups over 66 months.

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“How to build a cancer vaccine, and whether they will work this time” by Abhishaike Mahajan

LessWrong (30+ Karma)

“How to build a cancer vaccine, and whether they will work this time” by Abhishaike Mahajan