SHANGHAI (Reuters) - China s largely rubber stamp parliament has expelled disgraced senior politician Sun Zhengcai, once considered a contender for top leadership, state media said on Saturday, paving the way for formal criminal charges to be laid against him. The expulsion removes Sun s immunity from prosecution as a member of parliament. The announcement, carried by the official Xinhua news agency, gave no other details.  Sun was abruptly removed from his post as Chongqing party chief in July and replaced by Chen Miner, who is close to President Xi Jinping. Later that month, he was put under investigation and in September, the party announced he would be prosecuted for corruption. Sun was accused of leaking secrets, bribery and abusing his power. Chongqing is perhaps best known outside China for its association with Bo Xilai, its disgraced former party boss. He, too, was once a contender for top leadership. He was jailed for life in 2013 after a dramatic corruption scandal. It has not been possible to reach Sun or a representative for comment since he was put under investigation. It s unclear if he has been allowed to retain a lawyer.  