A cannabis extract may have a "deadly" effect on melanoma skin cancer cells.  Researchers from Charles Darwin University and the Royal Melbourne Institute of Technology in Australia found a cannabis extract in a laboratory setting, has a "deadly" effect on melanoma cells.  Skin cancer is the most common of all cancers in Panama and around the world. Panama is 9 degrees from the equator and most expats do not realize the sun's damage to their skin in this country.  Melanoma accounts for only about one per cent of skin cancers but causes around 80 per cent of skin cancer deaths, according to the Cancer Society.  The anti-cancer effects of a specific extract from Cannabis sativa forced melanoma cells into a "programmed cell death" known as apoptosis, according to the study published in Cells journal.  Biotechnologist and co-author of the study Nazim Nassar said: "We know today how this extract attaches to the receptor on the cell surface and changes the messages to the inside of the cell to manipulate the normal growth, to force it to go into [a] death progress. Before we take this to human trials, we have to go through animal trials, we have to make sure that these products are safe and effective. And more importantly we need to find the way to deliver (the extract) directly to the cell. Probably here we're looking at something topical or subcutaneous under the skin that will deliver the medicine directly to the target cells."