Renegade cell

We were enjoying a family video the other night recorded in ’94 during a blissful summer vacation at Bear Valley, California. We don’t often hook up the old VCR player, so hadn’t watched this particular video in years. It was fun to see Nick and Allie at ages 4 and 6 cavorting around a swimming pool with friends, and everyone basking in the High Sierra sunshine. Ellen turned the camera at one point on me reclined on the patio looking healthy and happy. I was wearing running shorts, sunglasses and possibly the deepest tan of my life. The words I then uttered on the video gave us both chills: “This is probably the best case of skin cancer I’ve ever had.”

I thought I was being funny. What I may have been was prophetic.

I will admit that I overdid it in the sun for most of my life. I never went out of my way to tan, but neither did I make much effort to cover up. I played golf hatless for years and, whenever I could, went shirtless. I can recall while in college burning so badly once that my chest and abdomen blistered. It wasn’t until I was first diagnosed with melanoma that I learned that sunburns during childhood are a major risk factor for skin cancer. In my defense, I’ll add that most everyone in those days was ignorant of the danger of too much sun. What has become an epidemic of melanoma hadn’t yet been noticed.

It’s impossible to know for sure if my melanoma was induced by UV radiation. It stands to reason that it was; more than 65% of all melanomas are. My primary tumor, detected in 2006, started in a mole on the side of my left leg near the knee, where it soaked up UV rays for years. It’s sobering to think that the cancer that has now metastasized throughout my body started with a genetic mutation in a single renegade cell. That fateful event could have occurred decades ago.

At its most basic level, cancer is a disease of damaged genes. I’ve read that every human cell sustains thousands of mutagenic attacks every day. Nearly all of them fail. The body places numerous obstacles in the path of cells intent on turning into tumors. The mutagens that cause cancer can come from UV light, but also from chemicals to which we’re exposed, air (and smoke) that we inhale, even food that we eat. No one can maneuver through life free of the statistical possibility of contracting cancer. About 40% of us will it at some point, of whom half will die of it.

It’s hard to imagine the epic battle that’s being waged in our bodies at the cellular level. Robert Weinberg, a cancer biologist at MIT, calls the rock-solid stability of the cell’s genetic database “a mirage.” The constancy of our genome is the result of a high-wire balancing act, he says—a permanent struggle in which an ever-vigilant repair apparatus continuously fights off genetic chaos.

But fear not. As threatening as this description sounds, the numbers actually work hugely in our favor. In a lifetime of 70 years, a human body produces about 10 million billion cells. In theory, there’s an opportunity for disaster every time one of those cells divides, which is when a mutated gene would be replicated. Set in that context, the fact that only one out of every five Americans dies from a malignancy doesn’t seem so bad. Since cancer is mostly a disease of older people, it wouldn’t even be a major category of death if we hadn’t done such a great job of curing infectious diseases and minimizing fatal accidents. A farmer can’t get cancer if he rolls a tractor over the top of himself when he’s 35.

The 1-cm nodule that’s currently lodged in my buttocks contains about a billion cells. The road it’s traveled to get there is beyond my comprehension. I’ve read enough of Weinberg to know, however, that it’s the end product of a long, multistep sequence of genetic events of exquisite complexity. I’m not about to call it beautiful, but that tumor is truly wondrous in its capacity to have outwitted tumor suppressor genes, apoptotic cellular mortality, and the killer T cells of the immune system. The body is literally built to defeat cancer, but it doesn’t possess zero-defect efficiency. There are obviously people in whom a single cell, damaged by the sun, can go mad and start to divide uncontrollably. Unfortunately, I’m one of them.