Science Friction_ Where the Known Meets the Unknown - Michael Shermer [65]
I’ll never forget that appointment, or when it was—October 1992. I remember because it was in the middle of the presidential debates between George Bush and Bill Clinton, and the neurologist asked my mom who was running for president. She didn’t know. Minutes later they were wheeling her in for a CAT scan. We returned after lunch to see the results. Since I was still “Dr.” Shermer, I was taken into the inner sanctum to see the results. I nearly fainted at what I saw—a massive tumor filled the front half of the left side of my mom’s skull, smashing her neurons against the back of her brain case. Through a shaky voice I explained to her what was going on, and that the solution would be major brain surgery, which can be extremely risky. But because her brain was squashed and she was not thinking clearly, she just shrugged and quietly acknowledged, in a small but sweet voice, “Okay.”
My mom’s tumor was a meningioma (originating on the meninges, the protective lining of the brain), which are far more common in women than men—the ratio ranges from 1.4:1 to 2.8:1—and cluster, curiously, in Los Angeles County, where we live. (Tragic irony: the psychiatrist who diagnosed my mom with depression was herself later diagnosed with the same type of brain tumor.) Fortunately, most meningioma tumors are successfully resected. Indeed, within days of the surgery her brain filled back into the hole and my mom was back to her bright and cheery self—what a remarkably recuperative and pliable organ is the brain.
Unfortunately, my mom might be another data point in support of Harvard Medical School surgeon Judah Folkman’s controversial angiogenesis theory of cancer, which he developed in the 1960s while conducting research for the U.S. Navy. Folkman noticed that tumors planted in isolated organs in glass chambers all stopped growing at a certain size. Their size range should have exhibited the classic bell curve, so he deduced that it was a lack of blood vessels in the tumors that prevented their continued development. In a 1971 paper in the New England Journal of Medicine, Folkman outlined his theory in four stages: (1) blood vessels in tumors are new, which means the tumors have to recruit them; (2) the tumor recruiting agent is TAF, or tumor angiogenesis factor; (3) the tumor secretes the TAF, which draws blood vessels to it; (4) once the production of TAF is terminated, the tumor ceases to grow.
By the 1980s, Folkman had discovered a number of angiogenesis inhibitors, including interferon and platelet factor 4, and in the late 1990s endostatin and angiostatin were found to be highly effective retardants of mice tumors. Today about twenty different compounds are being tested for their antiangiogenesis capacity, including Avastin and Erbutix, but thus far none of the angiogenesis inhibitors has been consistently effective in attenuating tumor growth in humans.
Most interesting to me was Folkman’s contention that tumors secrete their own angiogenesis inhibitors that prevent other tumors from initiating angiogenesis programs. Remove the dominant tumor, however, and you eliminate the angiogenesis inhibitors, thus allowing other dormant tumors to spring to life. Sure enough, within months of my mom’s initial brain surgery, two new tumors appeared. Fortunately they were within reach of the surgeon’s scalpel, but their removal in March 1993 apparently allowed other quiescent