sentence1: The seemingly eternal flame of the American soap opera Guiding Light has been extinguished. CBS, the network which airs the serial drama in the United States, has announced its cancellation after 72 years. Guiding Light, which entered the Guinness Book of World Records as the longest-running dramatic series in the world, started on radio in 1937 as a series of stories about faith, in which characters beset with troubles would talk to trusted Reverend Ruthledge, the keeper of "the guiding light" which shone from his window. Over the years, the theme of "the guiding light" became more muted and the series shifted focus to a middle-class German immigrant family, the Bauers. The show has been produced on television and seen nearly every weekday since June 30, 1952.
sentence2: CBS is an American TV network.