Researching my book, Live Full Throttle: Life Lessons From Friends Who Faced Cancer, I interviewed more than 100 people who told me stories about everything—from how the disease altered the trajectory of their lives, to how a cancer diagnosis changes the simple act of human conversation.

Here is what I learned: while we all know someone with cancer or another daunting illness, few of us know how to talk about it. Because nobody wants to be “that person” who says the wrong thing, many of us hold back from saying anything at all.

But when friends and family hold back, the unintended consequence for the person with cancer is feeling alone and unsupported.

Read: Six ways to respond when someone tells you about a scary diagnosis