How do ER, PR and HER2 affect staging?

In general, having receptors present (ie. ER+, PR+ and/or HER2+) lowers the stage and lacking receptors (ie. ER-, PR-, and/or HER2-) increases the stage.

A patient with triple positive breast cancer can shift from Stage II to Stage I depending on TNM and tumor grade

Likewise, a patient with triple negative breast cancer can shift from Stage II to Stage III
Having receptors allows for medical treatments targeting the receptors which improves outcomes