Give me an example how to use it

The plugin cannot currently show only terms with a common parent term. For this I would recommend a taxonomy specifically to hold cancer types. You would then show the cancer types directly from the cancer-type taxonomy and also apply the category of “cancer”.

So you would have two taxonomies: Cancer-Type and Category

In the Category taxonomy you’d have a single term labelled “Cancer” which you apply to all cancers.

In the Cancer-type taxonomy you’d list each of the types of cancer and show this using the shortcode:

[a-z-listing taxonomy="cancer-type" display="terms"]