(WJW) – Anna Cardwell, the daughter of “Mama” June Shannon and the sister of Alana “Honey Boo Boo” Thompson, has stage 4 cancer.

Anna “Chickadee” Cardwell was diagnosed with stage 4 adrenal carcinoma — also called adrenocortical cancer — in January, according to PEOPLE.

The National Cancer Institute (NIH) states that it is “a rare disease in which malignant (cancer) cells form in the outer layer of the adrenal gland,” and symptoms include abdominal pain.

PEOPLE reported that the cancer was found in Cardwell’s liver, kidney and lung after the 28-year-old complained of stomachaches.

She reportedly went through her first round of chemotherapy last month.

According to Cleveland Clinic, doctors diagnose only about one case of this rare cancer per 1 million people each year.

It’s unknown what causes it, though the NIH states that certain genetic conditions increase the risk.

Cardwell appeared on TLC’s “Toddlers and Tiaras” and later “Here Comes Honey Boo Boo” with her mother and sister.

Cardwell, Shannon’s eldest daughter, is a mother to two children.