Three point eight billion years ago, cellular life evolved.
That’s just an educated guess; details must be resolved. (1)
The molecules and pathways had evolved in times gone by
From atmospheric gases sparked by lightning in the sky. (2)

Reactions inside bubbles evolved packets of pathways.
And lots of packets fusing led to cells we see today.
Prokaryotes, eukaryotes became autonomous.
This took about two billion years: (to priests that’s blasphemous.) (3)

One point five billion years ago, another huge advance:
For some cells stuck together, a coordinated dance.
Such multicellularity at first was only slime.
But then, new shapes and sizes made a brand-new paradigm.

Such multicellularity produced a benefit.
For cells working together had made the prerequisite
For differentiation in the “boldest” of the blobs,
Which led to different organs, each performing different jobs.

In genetic reproduction, we know mistakes are made.
The “good” mistakes help cells evolve, for “bad,” a price is paid.
For some mistakes are fatal; some kill quickly; some are slow.
And that’s the root of cancer from a billion years ago.

And cancer gets another property from way back when.
From fifteen million years ago, we’ve found the origin.
Placentas must invade into the endometrium,
Establishing their blood supply for nutrients from “mum.”

Mistakes that DNA will make each time it replicates,
Invasion of placentas when a mother incubates:
When these occur at once in any organ we possess,
Then, what we know as cancer may produce a fatal mess.

So, cancer is one price we pay for how we have evolved.
In variation and selection, errors are involved. (4)
Sometimes they’re beneficial but there is a flaw within.
For sometimes they cause cancer, evolution’s evil twin.

(1) All time estimates herein are from Wikipedia. You may look them up if you are so motivated.
(2) Stanley Miller and Harold Urey, Science,1953
(3) I refer you to the first two chapters of Genesis in the Bible.
(4) Charles Darwin did not know of genetic mutation in DNA. He used the terms: “variation and selection.”