‘We were excited by all this and we went after all different kinds of childhood tumours,’ Fraumeni told me. ‘We found not only associations between the tumours and the anomalies, but between tumours and tumours. Kids with one cancer sometimes developed a second cancer, unrelated to the first. We found that some of them were related to treatment – radiation and chemotherapy – but a lot of them were not, so it led us to conceptualise the notion that genetic susceptibility can result either in multiple tumours in the same individual, or multiple cancers scattered over the family tree.’
By this time, Fred Li, also a paediatric oncologist by training, had joined their tiny unit. ‘Fred was a wonderful guy,’ commented Fraumeni. ‘He was a prince. Easy to work with, very bright, very modest – he added a tremendous amount to our group.’ (Fraumeni has a quaint habit of describing any man he admires – including Alfred Knudson, whose work on retinoblastoma, you will recall, led to the discovery of tumour-suppressor genes – as ‘a prince’.) The story of the syndrome to which he and Li gave their names began with a survey of children with adrenocortical tumours – a type of cancer that involves the outer layer of tissue of the adrenal glands. These tiny organs sit atop the kidneys and produce the hormones that control many of the vital functions of living, such as heart rate, blood pressure, the fight-or-flight response to stress, growth and sexual characteristics. ‘Adrenocortical tumours are very, very rare,’ said Fraumeni, ‘so we had to go to about 10 hospitals to get 21 cases. And two of them developed brain tumours . . . Unusual!’ he said, pausing for emphasis. ‘Then when we finished that survey, I got a call to say that a third case had developed a brain tumour and the family was riddled with sarcomas. That suggested to me there was enemy action . . . Three cases like that was unusual to say the least. So there were all these little clues coming up that something was going on.’
The eureka moment came when a family was referred to Fred Li in which two young cousins had rhabdomyosarcoma (the muscle tumour that afflicted John Berkeley, whose story opened this chapter); the mother of one child, still in her twenties, had breast cancer; and the father of the other had acute leukaemia. ‘It was explosive, you know, so much cancer at the same time,’ commented Fraumeni. The two doctors homed in on the family, taking a detailed medical history across the generations that revealed an abundance of cancers, sometimes with multiple tumours in the same individual. ‘That was it – we knew there was a syndrome.’
Thoroughly caught up in their detective work by now, the two returned to their multi-centre survey of childhood cancers and pulled out the cases of rhabdomyosarcoma for further investigation. Among these they found another three families in which the children’s tumours were associated with cancer in their still-young parents. Convinced they had uncovered something important in a field that still had little clue as to how and why children should be afflicted by a disease normally considered to be caused by the ravages of age and long-term exposure to harmful environments, they rushed to prepare a paper for the Annals of Internal Medicine as quickly as they could. ‘The thing that took the longest time was deciding what to call our syndrome,’ laughed Fraumeni. ‘Fred was more conservative than I was and we ended up with a question mark after the words “a familial cancer”.’
The year was 1969, way before the genetic basis of cancer had been convincingly demonstrated, and most of the seagulls on the roof were looking to viruses. Li and Fraumeni’s paper with its suggestion of a familial syndrome – by definition genetically based – was received with frank scepticism. A handful of familial, and therefore hereditary, cancers were already known, but they tended to give rise to the same tumour type in related cases – either breast or colon or ovary, for instance – and to affect adults. ‘Our syndrome was unusual in that those affected were all children and very young adults – and a bizarre array of tumours . . . Every conceivable cell type, from leukaemias to gliomas to sarcomas to adrenal tumours to breast cancer. And there were some other strange tumours like choroid plexus tumours, which are in the lining of the brain where the cerebrospinal fluid circulates. These tumours have come up so often in LFS that they’re almost pathognomonic (i.e. a defining characteristic of the disease). It’s like adrenal cortical cancers in children – when you see them, you think LFS.’
The sheer variety of tumour types was what puzzled the sceptics. Some suggested that a virus, transmitted from mother to child during pregnancy and birth much like HIV, was behind the family pattern. Others said there was no real pattern and that what they were seeing was ‘just the play of chance’. But while, as good scientists, they had to keep open minds, Li and Fraumeni were pretty convinced that a gene or genes were at the root of the clusters they had observed. They decided to keep a close eye on the four original families in their survey, and over a 12-year period they saw a further 16 cases of cancer develop – all of them part of the same constellation of tumours that characterised their syndrome.
During this time two other groups had joined the field of familial cancer epidemiology: one led by Louise Strong at MD Anderson in Houston and the other by Jill Birch at Manchester University in England. Together they provided much new evidence in support of Li and Fraumeni’s genetic hypothesis – and, incidentally, were responsible for the name Li-Fraumeni syndrome, or LFS, creeping into the medical literature and common parlance in the 1980s. Almost another decade was to pass, however, before mutant p53 was identified as the gene bringing grief to the unfortunate families.
HOMING IN ON THE RESPONSIBLE GENE
In the late 1980s Fred Li, then Head of Cancer Epidemiology and a practicing oncologist at the Dana-Farber Institute in Boston, was joined on the staff by a young Canadian named David Malkin, trained in paediatrics at Toronto’s Sick Kids Hospital, who was looking to gain some experience in children’s cancers to take back to the clinic in Canada. But the time he spent with Li – whom he describes as ‘a gentleman and a scholar; not physically imposing but with a real presence, and extraordinarily knowledgeable’ – gave Malkin an appetite for research, and he decided to pursue a career as a scientist alongside his work in the clinic seeing patients. He got a position as a postdoc with Steve Friend, the scientist who had discovered the first tumour-suppressor gene, Rb, just three years earlier. Friend had recently left Weinberg’s lab to set up on his own at Harvard, and over a casual meal in a restaurant he and Malkin brainstormed ideas for a research project to work on together. ‘Steve explained that he liked working with Fred (Li) and they were interested in exploring the genetics of this weird syndrome. I knew relatively little about LFS at the time,’ commented Malkin, ‘but it sounded intriguing.’
With a vast arena to work in and no clues to guide them, the two decided to start their search for the faulty gene by looking at Rb – if only because, with an inherited condition, a malfunctioning tumour suppressor that would leave carriers unprotected against cancer seemed like the most obvious candidate. Rb was familiar territory to Friend and there was little to excite their interest in p53, which had yet to emerge from the doldrums of being miscast as an oncogene. Coincidentally, the two scientists drew a blank with Rb just as big things began to happen again with p53. In 1989 Suzy Baker and Bert Vogelstein in Baltimore revealed that wild-type p53 was in fact a tumour suppressor, and later that same year scientists working with mouse models in Toronto published a paper describing the multiple tumour types that developed in animals with mutant p53. The constellation of mouse tumours didn’t exactly match what oncologists were seeing in families with LFS, said Malkin, but it was a dramatic enough demonstration of p53’s broad effect to make the researchers switch their focus to this newly revealed tumour suppressor.
Working with material provided by members of LFS families seen by Fred Li and Louise Strong in their cancer clinics, the two scientists set about isolating p53 to look for possible mutations. In those days it was an almost infinitely laborious process of cloning and sequencing stretches of DNA one after another until they found their target gene. ‘A lot of seque
nces didn’t work, and it was well over a year before we had our first hit that we knew was real,’ commented Malkin. ‘I remember I looked at the gel; I sequenced the gene; I compared it against the normal p53 and there was the mutation. We were very lucky because the first one that popped up was at codon 248, which happens to be about the most common mutation we have in p53. That was fortuitous, because if it had been in some slightly more obscure site we may not have paid so much attention to it.’
He and Friend knew there were months of hard work ahead if they were to confirm the finding and look for more mutations but, once they realised they were on the right track, the whole lab went into overdrive. ‘That’s where you turn your alarm clock off and you’re just in the lab the whole time because you’re having a lot of fun!’ said Malkin with a grin. ‘That summer of 1990 was very exciting. We were in a brand new building, it had a beautiful view over Boston Harbour . . . There was no good reason not to enjoy yourself and the whole lab was really on fire.’
Having finally put the picture together of what was happening in people with LFS, Malkin and Friend hammered out their paper for Science at a nearby pizza restaurant, the table scattered with handwritten pages amid the plates of half-eaten food, and the two preoccupied scientists oblivious to the comings and goings of other diners. This they knew would cause a stir because, although LFS appeared to be extremely rare, identifying mutant p53 as the root cause of a problem with such diverse manifestations confirmed the gene’s central importance in human cancer. Not just in lab dishes and genetically engineered mice, but in real people like us. Here too was a means of identifying people at risk in cancer-prone families who, with intensified screening, could be treated for lesions before tumours had a chance to develop.
Over the years mutations have been reported in many different sites in the p53 of people with LFS, just as they have in so-called somatic cases (people who have developed a mutation during life rather than inherited a mutant gene at birth). The most common ones are those that affect p53’s ability to attach itself to DNA in order to switch on other genes (i.e. to act as a transcription factor). Researchers have discovered too that girls born with LFS have a lifetime risk of developing cancer of more than 90 per cent, while the comparable risk for boys is around 75 per cent, with breast cancer most probably accounting for the higher risk to females. Though most oncologists recognise a typical pattern to LFS, said Fraumeni, ‘One of the things that I’ve learnt in studying these families is that the susceptibility is not just limited to the so-called classical tumours – brain, adrenal, breast, sarcomas. It really is almost across the board; almost every tissue, I think, has an increased risk.’
LIVING WITH LFS – LUANA LOCKE CONTINUES HER STORY
These were the odds that Luana Locke faced when she learnt that her family had Li-Fraumeni syndrome, giving her an explanation at last for why lightning kept striking in the same spot. When Luana’s mother, sister and aunt died of cancer in the early 1970s, LFS was barely recognised outside of academic circles and had certainly not been named. It was not until her Aunt Rina’s youngest daughter, Jessica Zendri, in Italy developed bilateral breast cancer and an adrenocortical tumour that a geneticist in Milan discovered the germline mutation in p53. He suggested that Luana be tested for the same genetic defect back home in Canada, and he recommended to her someone with special expertise, David Malkin, now working again at Sick Kids Hospital in Toronto.
After all she had been through, Luana was not surprised to receive the news that her test result was positive, she said. But then all of a sudden the focus was shifted away from her. ‘All I remember hearing was, “You have a 50/50 chance of passing this on to your child.” Now it was all about my son: does he have a mutation, does he not? So it was just about getting him tested, because I needed that knowledge; I needed to know.’
Subsequently, as she and her husband Paul sat through genetic counselling, and consulted again with Dr Malkin, the implications of her diagnosis and the possibility that Lucas, now four years old, also carried the mutant gene, were carefully explained. ‘Everybody we spoke with did their due diligence,’ she commented. ‘“These are the things you really need to consider: the potential for false positives and false negatives; that this is a decision you’re making on behalf of your child, so you’ll need to think about at what stage you tell him. What if he’s the type of person who, in adulthood, says he wouldn’t have chosen to be tested; he wouldn’t have wanted to know?” All of these things they were telling me . . . but I had already stopped listening. I sat there and I went, “Aha, yeah, okay, I have to think about that.” And all along an inner voice was just saying, “He’s going to be tested; I need to know.”’
What did Paul feel? ‘I’ll admit, there wasn’t a choice there, I would have played the mother card, because I’m that type of person. There’s no way somebody’s going to hold a secret that’s just within my grasp and me not know about it. That would have killed me. And secondly, I’m the eternal optimist. For me it was, “Huh! He’s not going to have the mutation! Just give me the results so we can close that chapter and move on.”’
After a period meant for reflection, the Lockes took Lucas along for testing. But none of the messages had sunk in and Luana was not prepared for the result. Sitting across a small table from me in the corner of a busy restaurant in Toronto 12 years later, she vividly recalled the meeting at the clinic. ‘The genetics counsellor who was working with Dr Malkin’s programme came with this manila envelope. She sat us down, Lucas was there too, and she started talking science, right? She was talking about the gene, and this strand and that strand, and I was just following along pleasantly. I was like, “Okay . . . she’s just stringing us along and this is going to end with: ‘. . . but there’s nothing there; clean bill of health!’” And so when she said, “. . . and we did find . . .” Locke’s jaw drops as she recreates her moment of shock. ‘I thought, “I’m sorry, what?” I didn’t say it out loud, but I remember thinking, “Okay, wait a minute, I was not prepared for this. That’s not the way this story was going to end for me.”
‘I think the poor woman who was telling us this stuff must have been thinking, “When is this woman going to start getting that I’m going somewhere with this story? Because she’s still smiling along. . . .”’ Only then did all the questions Luana and Paul had been advised to consider in advance flood their minds. ‘I stopped and I thought of every single one of them. Oh my gosh, what if he doesn’t want to know? How am I going to be the keeper of this information and knowledge? And am I going to treat him differently? Of course I am . . . We just felt extremely protective.’ That night she and Paul took Lucas into bed with them – a practice they had never indulged before – and held on to him tightly.
With time, the Locke family came to terms with LFS. They fell into a routine of regular three-monthly visits to Sick Kids for Lucas to be screened, and in due course allowed themselves to consider having another child. Traumatised by the regular tragedies in his extended family, Paul was only ready to go ahead provided they agreed to screen the unborn baby and consider termination if he or she carried the mutant gene. But abortion was never really an option, commented Luana. When she got pregnant and began to think of screening, she realised she could never go through with it. She was haunted particularly by the question: had such a test been available when her mother was starting a family 47 years ago, would she have chosen to abort Luana and her siblings?
So Lucas’s little sister Juliet was born in 2006. Once again Luana believed she would be okay. ‘After all,’ she said, ‘two kids, 50/50 chance . . . I’d had the 50 per cent already.’ But once again her optimism was misplaced. Paul and she were given the news that Juliet too is a carrier of the mutant gene, and they will need to help their daughter, as they are helping their son, face up to life in the shadow of cancer.
As John Berkeley has found, coping with LFS can be an isolating experience. Until recently, however, the condition was considered to be mercifully rare. As of 2
011, only about 500 families worldwide had been reported in the literature with germline mutation of p53. But that was before Dr Maria Isabel Achatz revealed what was going on in southern Brazil.
CHAPTER SEVENTEEN
The Tropeiro Connection?
In which we learn about Li-Fraumeni families with an atypical p53 mutation thought to have been introduced to Brazil by an individual settler from Europe in the mid-19th century.
***
Nothing in life is to be feared, it is only to be understood.
Marie Curie
São Paulo is a giant sprawl of a city with extremes of wealth and poverty. Rough wooden shacks cluster in hidden spaces at the foot of skyscrapers of glass and steel, and here and there destitute people huddle in doorways on streets along which their fellow citizens in designer clothes hurry to work or shop or meet up with friends. Everywhere, huge tropical trees, as if in dogged defiance of the relentless spread of concrete and tarmac, buckle the pavements with their roots, drop their blossoms on passers-by and harbour chattering birds in their leafy crowns. This is the city where Maria Isabel Achatz lives and where she began to uncover an extraordinary story of familial cancer as she worked at the huge, modern A C Camargo Hospital. And it is where I visited her in the late summer of 2012 to hear her story.
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