Uni's cancer discovery sparks hopes of new therapyLocal | Carain Yeung 7 Apr 2017
Chinese University of Hong Kong researchers yesterday said they have discovered the mechanism of the microenvironment for cancer growth, which potentially could be developed into new therapy.
Existing medications target cancer cells but mutations leave therapies useless after a period of time due to drug resistance, said Patrick Tang Ming-kuen, research associate of the university's anatomical and cellular pathology department.
"Even if you chop down the tree, it can grow again. And that's why we have to look at how we can change it from the soil, and that is the microenvironment," he said.
The university in 2012 started studying the immune escape mechanism for cancer. Natural killer cells are present in this "soil" of non-cancerous cells in a tumor and they are "the first-line army against cancer," said Lan Hui-yao, biomedical sciences professor and associate dean of the CUHK Faculty of Medicine.
But Lan said cancer cells are like stealth aircraft that can evade the body's immune system and his team found the mechanism.
In further investigations, researchers studied the mechanism with two mice models - with invasive lung carcinoma and melanoma. Smad 3 was removed from the mice in the first experiment and it was found that the cancer growth became slower and there was also no metastasis.
Smad3 inhibitors were used on the experimental groups in the second experiment and cancer growth was measured after 15 days of treatment. The control group had a lung cancer tumor 1.2 grams in weight while the size dropped to under 0.2g for the experimental group.
Significant shrinkage was also observed in the group with melanoma, with the tumor less than 1.5g, compared with more than five grams for the control group.
Tang said the survival rate for the experimental groups reached 100 percent.
To Ka-fai, chairman of the department of anatomical and cellular pathology, said existing immunotherapy drugs only work on 20-30 percent of cancer patients while this potential therapy is expected to work for all. Lan said the team will improve the inhibitors in the next step to pave the way for clinical studies. The new medication will be available in 10 years at the earliest.