Why Pregnancy Linked Breast Cancer is More Aggressive

Breast cancer can happen to anyone, but when it shows up during or shortly after pregnancy, it’s called pregnancy-associated breast cancer or PABC. This type of breast cancer is rare, but it can be more aggressive than other forms. Scientists recently studied how this type of cancer works and found some important clues.

Here’s what they discovered and what it means.

What Makes PABC Different?

PABC grows and spreads more aggressively than breast cancer that isn’t linked to pregnancy. One reason for this is that PABC tumors are more likely to be basal-like. Basal-like tumors are a type of breast cancer that tends to grow quickly and is harder to treat. Nearly half of the PABC patients in the study had this type of tumor compared to only about 15 percent of patients with non-PABC breast cancer.

Tumor Growth and Gene Differences

Scientists used a tool to look at the activity of hundreds of genes in cancer cells. They found 73 genes that behaved differently in PABC. Some of these genes are involved in DNA repair and cell growth.

Think of DNA repair as your body’s way of fixing mistakes when cells divide. If something goes wrong with this process, damaged cells can grow out of control. This is one reason PABC tumors might grow faster.

Genes like DEPDC1, CCNA2, and PSAT1 were overactive in PABC tumors. These genes are part of how cancer cells multiply. On top of that, the researchers identified important genes like MYC and PTEN that control how fast cells grow and whether they survive.

The Role of the Immune System

Another key discovery was how the immune system behaves differently in women with PABC. The study showed that women who were diagnosed after giving birth (postpartum cases) had tumors with more immune activity.

The researchers noticed higher levels of PD-1, a protein that helps cancer hide from the immune system. They also found more immune cells like regulatory T cells and macrophages in these tumors. This may explain why postpartum breast cancer can behave differently than cancer that develops during pregnancy.

Why These Discoveries Matter

These findings help scientists understand why PABC is so dangerous. Tumors in PABC grow faster, repair their DNA poorly, and may interact with the immune system in ways that allow them to spread.

This research could lead to new treatment options. For example, doctors might focus on therapies that target the immune system or cell growth pathways. Treatments like immunotherapy, which helps the immune system recognize and attack cancer, might become more effective for postpartum cases.

What Can We Learn from This?

PABC is a reminder that cancer is not one-size-fits-all. It can behave differently depending on things like pregnancy or postpartum changes in the body. By understanding these differences, researchers can work toward better treatments and outcomes for people with breast cancer.

If you or someone you know is pregnant or recently gave birth, it's important to stay informed and talk to a doctor about any changes in your body. Early detection and awareness can make a big difference.