ESR1 and flatulence: In conclusion, this study highlights the importance of awareness of GAS, its diagnostic dilemmas and the need to recognize clinical, morphological features of GAS, the significance of IECC criteria to differentiate between HPVA and non-HPV associated ECA, and the role of p16, MUC-6, ER, PR and p53 immunohistochemistry in differential histopathological diagnosis.