SYDNEY, July 26 (Xinhua) -- A naturally occurring hormone could help make chemotherapy much more effective for many lung cancer patients, at the same time helping them avoid a kidney damage side effect from the usual treatment, according to Australian research findings released on Thursday.

When Professor Neil Watkins from the Garvan Institute for Medical Research and his team discovered that the protein activin was behind chemotherapy resistance and chemotherapy- induced kidney damage, it led them to develop the naturally occurring hormone follistatin - which blocks activin - to specifically treat inflammatory and fibrotic diseases.

Their lab tests on mice found that treatment of follistatin in combination with platinum- based chemotherapy caused lung tumors to shrink and more animals to survive longer, with kidney damage also prevented, the institute said in a statement.

"Because follistatin is a hormone already found in the human body, there is much less potential for toxicity than with other drugs used to reduce chemoresistance," said Watkins.

Research team member Kieren Marini said "discoveries like this one - a combination therapy that actually reduces damage while improving effectiveness of chemotherapy - are exceedingly rare in cancer research."

Their findings, published in the Science Translational Medicine medical journal, have laid the foundations to move this "combination therapy," of reducing damage while improving effectiveness of chemotherapy, to a clinical setting.

There are also plans to study other tumors where platinum chemotherapy is commonly used, such as bladder and head and neck cancers, said Watkins.