Substantial evidence has shown that tumors can emerge from a distinct, small population of cells known as cancer stem cells (CSCs), which have a vital role in the initiation, main­tenance, metastasis, drug resistance, and relapse of cancer. Hence, it is critical to identify drugs that selectively target and eliminate CSCs to induce a long-lasting therapeutic re­sponse and better patient outcomes. Modulations in epige­netic regulation contribute to cancer progression as it is cru­cial for both stem cell biology and chemoresistance. Poly­comb group (PcG) and trithorax group (TrxG) proteins are identified as the key modulators of cellular memory that di­rect whether a stem cell will self-renew or differentiate. The dynamic interaction of these two groups of proteins with op­posing effects on gene expression has opened up new avenues for understanding their role in tumorigenesis. Therefore, it is essential to elucidate the underlying mechanisms of aber­rant epigenetic modifications, without which designing drugs becomes implausible. The existing cancer treatments like ra­diotherapy and chemotherapy have major limitations owing to treatment failure and recurrence of cancer. However, the application of epigenetic therapy has shown promising ther­apeutic results in clinical trials with its ability to reverse the aberrant epigenetic modifications that result in cancer and chemotherapy resistance. Future research aimed at devel­oping drugs that are target specific is necessary to prevent off-target effects. To overcome the limitations of the current epidrugs, novel approaches like CRISPR/Cas9-based epige­netic editing are emerging as new hopes for targeted therapy in cancer. This article gives an overview of the till-date under­standing of the role of epigenetics in cancer stem cell biology and recent developments in epigenetic therapy.

J.B.S Haldane, a polymath with extraordinary intellectualqualities, contributed significantly to 20th-century biology,especially to evolutionary theory and genetics. Among hismajor contributions is a generalisation that has come to becalled ‘Haldane’s Rule’. It states that among the offspringborn to parents from two different animal races, if one of thesexes is absent, rare, or sterile, that sex is characterised byunlike sex chromosomes. Haldane’s rule remains an unusualexample of something like a law of nature in biology and thuscontinues to attract attention and debate. We discuss some ofthe more interesting attempts to explain why the rule works.