The 25-year-old had a tumour removed in July and returned a positive drugs test after the 2-2 draw with Cagliari on December 1.
However, Sassuolo have confirmed Acerbi failed the test because of an increase in the levels of levels hormone hCG due to a relapse of the cancer.
Following medical tests, the club outlined the treatment path ahead for Acerbi, adding that an appeal had been lodged with the anti-doping commission
"Following consultation with the National Institute for Tumours in Milan and Professor Roberto Salvioni, the pharmacological anti-tumour protocol the player will undergo was defined," Sassuolo said on their website.
"Ace, we are all with you!"
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