Lexicographer review — Page 22 of 37 S3

Because of the isolation of the retinoblastoma tumor-suppressor gene , it became possible last January to find out what threat the Quinlan baby faced .

A test using new “ genetic probes “ showed that little Will Quinlan had not inherited a damaged retinoblastoma supressor gene and , therefore , faced no more risk than other children of developing the rare cancer .

“ It made our New Year , “ says Mr. Quinlan .

This test was the first to predict reliably whether an individual could expect to develop cancer .

Equally important , the initial discovery of the gene that controls retinal cell growth , made by a Boston doctor named Thaddeus Dryja , has opened a field of cancer study , which in recent months has exploded .

The finding riveted medicine .

It was the first time anyone had showed that the loss of both copies of the same gene could lead to the eruption of a cancer .

“ It was extraordinarily satisfying , “ says Dr. Knudson , now at Fox Chase Cancer Research Center in Philadelphia .

“ I was convinced that what was true of retinoblastoma would be true for all cancers . “

It was an audacious claim .

Gradually , a coherent picture of cancer development emerged .

If both copies of a certain gene were knocked out , benign polyps would develop .

If both copies of a second gene were then deleted , the polyps would progress to malignancy .

It was clear that more than one gene had to be damaged for colon cancer to develop .

Their report galvanized other molecular biologists .

Gradually , a coherent picture of cancer development emerged .

If both copies of a certain gene were knocked out , benign polyps would develop .

If both copies of a second gene were then deleted , the polyps would progress to malignancy .

It was clear that more than one gene had to be damaged for colon cancer to develop .

Their report galvanized other molecular biologists .

Gradually , a coherent picture of cancer development emerged .

If both copies of a certain gene were knocked out , benign polyps would develop .

If both copies of a second gene were then deleted , the polyps would progress to malignancy .

It was clear that more than one gene had to be damaged for colon cancer to develop .

Their report galvanized other molecular biologists .

When they found it last winter , Dr. Vogelstein was dubious that the search was over .

His doubts stemmed from the fact that several years earlier a Princeton University researcher , Arnold Levine , had found in experiments with mice that a gene called p53 could transform normal cells into cancerous ones .

The deletion Dr. Vogelstein found was in exactly the same spot as p53 .

But Mr. Levine had said the p53 gene caused cancer by promoting growth , whereas the Johns Hopkins scientists were looking for a gene that suppressed growth .

Despite that , when the Johns Hopkins scientists compared the gene they had found in the human cancer cells with the Mr. Levine 's p53 gene they found the two were identical ; it turned out that in Mr. Levine 's cancer studies , he had unknowingly been observing a damaged form of p53 -- a cancer-suppressing gene .

In a report out last week , John Minna and colleagues at the National Cancer Institute say that about half the cells taken from lung cancer tissue they tested are missing this gene .

There also are reports from several labs , as yet unpublished , of missing p53 genes in tissue taken from kidney , brain and skin cancers .

At the same time , the Johns Hopkins team and others are rushing to pinpoint other tumor-suppressor genes .

Dr. Vogelstein hopes soon to isolate one on chromosome 18 , also involved in colon cancer .

Ray White in Utah and Walter Bodmer , a researcher in Great Britain , are close to finding another gene involved with some types of colon cancer , thought to be on chromosome 5 .

Dr. Vogelstein hopes soon to isolate one on chromosome 18 , also involved in colon cancer .

Ray White in Utah and Walter Bodmer , a researcher in Great Britain , are close to finding another gene involved with some types of colon cancer , thought to be on chromosome 5 .

Dr. Minna believes people who inherit a defective gene somewhere on one of their two copies of chromosome 3 are especially prone to lung cancer .

Recently , he and others reported that the retinoblastoma suppressor gene may also be involved in some lung cancers , as well as several other more common cancers , too .

Where these discoveries will lead , scientists can only speculate .

Where these discoveries will lead , scientists can only speculate .

Already two major pharmaceutical companies , the Squibb unit of Bristol-Myers Squibb Co. and Hoffmann-La Roche Inc. , are collaborating with gene hunters to turn the anticipated cascade of discoveries into predictive tests and , maybe , new therapies .

Some researchers say new cancer drugs to slow or reverse tumor growth may be based on the suppressor proteins normally produced by the genes .

The idea would be to administer to patients the growth-controlling proteins made by healthy versions of the damaged genes .

It may even be possible to replace defective genes with healthy versions , though no one has come close to doing that so far .

Why ca not we teach our children to read , write and reckon ?

It 's not that we do not know how to , because we do .

It 's that we do not want to .