This is certainly going to be a subjective answer based upon the fact that you are looking for an interpretation of parallels made between Mary Shelley's Frankenstein and Suzanne Collins' The Hunger Games.
Both novels are, ultimately, a study in Nature verses Nurture. In regards to Frankenstein, the creature is a product of Nature. What this means is that the creature is denied by Victor and the creature fails to be nurtured. Instead, the creature must come to understand life through its interpretation of how life is according to the environment around it. The creature finds little sympathy in the world and is, instead, forced to become a monster based upon the fact that it must learn to survive based upon how the world around it treats it.
As for the characters in The Hunger Games, Kantiss is a perfect example of how Nature can change a person. Kantiss is raised in a loving home with supportive people around her. The fact that she changes when placed into the games shows the impact that Nature has on her as a person. Katniss is not the same person she was leaving the games as she was entering the games. Instead, she learned things about herself that she did not know. This "education" was not based upon the nurturing nature of those who cared about her. Instead, her changed was forced by the environment around her while competing.
Both Katniss and the creature were products of their environment. Their environments were responsible for their creation as they existed at the end of each of the novels.