"Casting light upon" could also be replaced with other synonyms like "shedding light on," "bringing to light," "illuminating," "clarifying," "revealing," "exposing," "uncovering," "elucidating," "enlightening," or "unveiling." Each of these synonyms convey the idea of providing insight or understanding into a particular topic. The use of synonyms can help add depth and variation to one's language, creating a more engaging and informative message. Therefore, incorporating synonyms for "cast light upon" can enhance the clarity and precision of a written or oral communication.