Your gift is 100% tax deductible
Espa?ol
PDFs by language
Our 24/7 cancer helpline provides information and answers for people dealing with cancer. We can connect you with trained cancer information specialists who will answer questions about a cancer diagnosis and provide guidance and a compassionate ear.
Chat live online
Select the Live Chat button at the bottom of the page
Call us at 1-800-227-2345
Available any time of day or night
Our highly trained specialists are available 24/7 via phone and on weekdays can assist through online chat. We connect patients, caregivers, and family members with essential services and resources at every step of their cancer journey. Ask us how you can get involved and support the fight against cancer. Some of the topics we can assist with include:
For medical questions, we encourage you to review our information with your doctor.
Skin is made up of three layers—the epidermis, dermis, and hypodermis— and acts as a protective barrier between internal structures and the outside world.
The epidermis is the outermost layer and is mostly made of keratinocytes to form the skin’s protective barrier. The epidermis also contains melanocytes which control skin color and protects other skin cells from DNA damage by absorbing UV rays.
The dermis is the skin’s thickest layer. It provides support and contains nerve endings, sweat glands, oil glands, hair follicles, blood vessels, and lymph vessels.
The hypodermis (also called the subcutaneous layer) is a layer of fat and connective tissue below the dermis.
The American Cancer Society medical and editorial content team
Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.
Last Revised: December 13, 2022
American Cancer Society medical information is copyrighted material. For reprint requests, please see our Content Usage Policy.
Sign up to stay up-to-date with news, valuable information, and ways to get involved with the American Cancer Society.
We fund research breakthroughs that save lives. Your year-end gift helps find new treatments for cancer.