Malignant is an apt title. Besides the mother's cancer, the father is also malignant or causing harm in his relationships with both his wife and with his daughter Reese, the book's protagonist.
Fifteen-year-olds often live in many worlds, such as neighborhood, school, clubs, home. Reese juggles home, school, and her bff Brandon. Slowly, as her mother's health declines, Reese develops a malignancy of despondency and depression.
Interestingly, Kazmierski adds a malignancy to Reese's plant that she is to care for and write about for a semester. This was a genius device to use, but I think it could have been used even a bit more without being too heavy handed. The interactions with her teacher and Brandon in the greenhouse seemed to mirror some of the life events of others throughout the course of the novel.
The relationship that Reese had with her parents seemed almost lacking in true emotion and a mature love of parental units. There were words of love, but few actions that seemed constantly loving towards one another. Though I knew Reese loved them, she seemed more caught up in her own comfort and life than in helping her family and saying a good goodbye to her mother. I was surprised that I didn't see Reese interact with anyone besides Brandon. She and one girl smiled at each other, and Reese thought she might need to look for more friends than just Brandon, her bff, but we don't see this happening. I wondered why Reese seemed more of a recluse, if something in her life had impacted her.
The hint of friendship turning to romance is one point of caring that is clearly seen in the novel as first Reese's mother encourages her to ask Brandon to the Sadie Hawkins dance, and then a few days after her mother's funeral, her father tells her she should still go. The romance is a secondary plot line and doesn't overshadow the main story of how a teen lives through a parent's death without simple, clean resolutions. Life is messy and heartbreaking sometimes and this novel shows people how some individuals deal, or don't accept, a death in their family.