The primary purpose is to compare the impacts of intraperitoneal pressure (8mmHg versus 12 mmHg) and CO2 gas (cool, dry CO2 gas versus warmed, humidified CO2 gas) on gene expression in peritoneal tissues during laparoscopic surgery. We hypothesize that combined use of a low Intraperitoneal pressure (8mmHg) and warmed, humidified CO2 gas during CO2 pneumoperitoneum may be better in minimizing adverse effects on surgical peritoneal environment and improving clinical outcomes compared to the standard intraperitoneal pressure (12mmHg) and standard cool, dry CO2 gas.