Global alterations in epigenetic landscape are now recognized as a hallmark of cancer. Epigenetic mechanismssuch as DNA methylation,histone modifications,nucleosome positioning and non-coding RNAs are proven to have strong association with cancer. In particular,covalent post-translational modifications of histone proteins are known to play an important role in chromatin remodeling and thereby in regulation of gene expression. Further,histone modifications have also been associated with different aspects of carcinogenesis and have been studied for their role in the better management of cancer patients. In this review,we will explore and discuss how histone modifications are involved in cancer diagnosis,prognosis and treatment. Global alterations in epigenetic landscape are now recognized as a hallmark of cancer. Epigenetic mechanismssuch as DNA methylation, histone modifications, nucleosome positioning and non-coding RNAs are proven to have strong association with cancer. In particular, covalent post-translational modifications of histone proteins are known to play an important role in chromatin remodeling and thereby in regulation of gene expression. Further, histone modifications have also been associated with different aspects of carcinogenesis and have been studied for their role in the better management of cancer patients. In this review, we will explore and discuss how histone modifications are involved in cancer diagnosis, prognosis and treatment.