All means ‘every one’, ‘the complete number or amount’ or ‘the whole’. We use it most often as a determiner. We can use a countable noun or an uncountable noun after it: … When all refers to a whole class of people or things, we don’t use the: …

ALL definition: the whole of (used in referring to quantity, extent, or duration). See examples of all used in a sentence.

n. The whole of one's fortune, resources, or energy; everything one has: The brave defenders gave their all.

Acute lymphocytic leukemia (ALL), also called acute lymphoblastic leukemia, is a cancer that starts from white blood cells called lymphocytes in the bone marrow.

So what's the difference? First you need to understand the difference between "all" and "all the". We use "all" (without an article) when we're talking about the noun in general.

The overall five-year survival rate for ALL is 72%. That means that 72% of children and adults diagnosed with acute lymphoblastic leukemia will still be alive five years later.

Evidence for the role of the environment is seen in childhood ALL among twins, where only 10–15% of both genetically identical twins get ALL. Since they have the same genes, different environmental exposures explain why one twin gets ALL, and the other does not.

You use all to refer to a situation or to life in general. All is silent on the island now. As you'll have read in our news pages, all has not been well of late.