Which example from The Metamorphosis helps Kafka to establish a theme of isolation?

Gregor imprisoned in his room is an example of isolation. He is physically isolated from the rest of his family. The fact that he is turning into an insect also isolates him, not only from his family but, from humanity. Even before Gregor's metamorphosis, he felt isolated by his job and his role in the family.

which example from The Metamorphosis helps Kafka to establish a theme of isolationw