Leah Marks

Leah  Marks

My PhD was in Developmental Medicine and I am currently a Senior Lecturer in Medical Genetics at the University of Glasgow. I have also been a Senior Fellow of the HEA since 2016.

Location Glasgow University


  • Hi Ken, interesting point - there are continually 'mistakes' being made during the copying of our DNA when our cells divide. These do get repaired very readily by DNA repair mechanisms, which is just as well, otherwise cancers would be much more common. Some people do have these repair systems impaired which can predispose them to cancers.
    However there are...

  • Very good question Joshua! In short it is publically available information. I quote from this website <https://www.genome.gov/human-genome-project/Completion-FAQ>

    "Every part of the genome sequenced by the Human Genome Project was made public immediately, and new information about the genome is posted almost every day in freely accessible databases or...

  • Should be there now (and subtitles)

  • Hi Angharad, let me check up on that - there should be a transcript for it...

  • Hi there, there's a good image of the different groups on this webpage - along with more information on their characteristics


  • Hi Juha,
    If you're interested in this topic (and why in actual fact there is a special form of DNA which is left handed - called Z-DNA) here is a link you might find interesting


  • Sometimes drawing a family tree can be really difficult - and that reflects what can happen in the clinic. Not all patients will know all of their family history, and the clinician will just have to work with what is known.

  • Leah Marks made a comment

    Good to see you've been thinking about the question posed at the end of the video. Your answers are correct - chromsome, being much bigger than 1, has too many genes on it to be survivable with an extra copy.

  • We'll learn a bit more about both in the coming steps - both can be very detrimental to the cell/organism.

  • Yes that's always wise to be careful and respect others right to privacy.

  • Thanks Victoria - that's a useful suggestion and one which we'll hopefully be able to look into for the next run of the course.

  • Nice to see people still joining - we hope you find it useful! If you've got questions it's best to ask them in the current week as that's the one we'll pay most attention to. But feel free to work through the other weeks at your own pace.

  • No I've not heard of that - although I always think that a bit of knowledge of where we have come from in medicine can help inform current thinking and understanding!

  • Leah Marks replied to [Learner left FutureLearn]

    Yes - you're right - very well spotted :-) Have fixed that now! Thank you!

  • Leah Marks made a comment

    Nice to meet you all too - we'll try and answer as many questions as we can but it would be great if you can help each other out too!

  • Great to hear from you - keep the introductions coming! I'm glad that we've got people from such a range of backgrounds, hopefully there will be something for everyone here!

  • Sorry that you did't enjoy the videos - we purposely chose not to deliver them in lecture format as lectures been shown not to be the most effective way of presenting information. Short videos tend to work better in terms of engaging an audience. I've been reviewing the questions weekly (for the current week as mentioned in week 1) and answering them when...

  • Yes I would agree with your comments!

  • Hi Shabtai, I think the best way of explaining it is that the modifications that are made to the DNA (but which aren't base changes) can be passed down the generations from cell to cell. Does that make sense?

  • Some interesting information on this aspect (from a a patient's perspective) here:

  • Interesting point. In trials we are using drugs that we genuinely don't know have an advantage. Sometimes, if a drug is shown to have a marked advantage the trial will be stopped early to prevent disadvantage to those on the placebo.

  • @ReubenSoi It's very uncommon to have a predisposition to leukemia but there do seem to be some rare variants implicated in this - see this article

  • HI there,

    The mechanisms of resistance mechanisms are varied but can, for example, be because of BCR-ABL gene amplification or, more commonly because of mutations within the BCR-ABL kinase domain where the drug binds. More on this in the next step....


  • Good question - more on this in week 6!

  • Hi Sandra, Yes the videos were made several years ago - the course first ran in 2014. However we have updated various aspects of it since then e.g. by adding in immunotherapy. But in such a quickly moving field there will always be more up to date information and I would love to do another update this year.

  • Yes - the ability to target the radiotherapy more specifically certainly leads to less systemic effects.

  • It's certainly difficult to be sure are no rogue cells which have escaped - sometimes chemotherapy is offered just to mop up as many of these as possible.

  • Very good questions - we look at health economics a bit more in week 6!

  • If you click on the padlet link https://genome.cshlp.org/content/early/2017/05/16/gr.219915.116.full.pdf

    and then click the + sign in the bottom right hand corner I think that should work!

  • Yes you're right Rachael - if a condition is dominant both parents would only need one copy of the variant to be affected - and their child might inherit both unaffected copies.

  • I guess the key thing is that all genetic counselling is 'non directive' i.e. people are given the information to allow them to make informed choices - even if those choices might not reflect the decision the counsellor would have made for themselves.

  • These are all really interesting issues that you have raised - with some good points made!

  • Hmmm yes unfortunately it seems to be offline at the moment....

  • Have a look at this article which deals with that subject!


  • Welcome to everyone - whatever your motivation for doing this course is. We really hope you will find it informative and enlightening. If you have questions then try to post them in the current week as that's where we will be focusing on in terms of moderating the comments threads and discussions. But please do introduce yourself on here even if you are...

  • @ReubenSoi Pain in cancer can certainly be caused by the tumour pressing on nerves (or other body structures such as organs). Cancer Research has an informative section on this

  • We'll take a look in week 3 at how exposure to certain environmental factors (of which asbestos is one) can make people more likely to develop cancer - hopefully that will help explain it a bit.

  • Yes - if you think of the fact that in our bodies, errors in DNA copying are happening all the time. Most of these will be picked up and corrected, or will not matter but sometimes these changes escape the detection systems (particularly in cells with mutations in the detection systems themselves). Some mutations give cells a survival advantage by allowing...

  • Good question - that's something you'll hopefully learn more about as we go through the course. Week 4 has a couple of videos from a pathologist - one of the people who would be involved in 'staging' the cancer and in we'll talk more about resistance to therapies in week 5 and 6.

  • Hi Reuben, in NF1 you can get tumours developing in a number of different locations - see here for more information https://www.nhs.uk/conditions/neurofibromatosis-type-1/symptoms/

  • Yes there'll be plenty on this in the coming weeks- and more resources in a subsequent step this week if you are interested.

  • Since the vaccine doesn't protect against all forms of HPV screening is still recommended. When and how often has been debated - can anyone find any useful resources on this?

  • Good question - what do other people think? Is it that early detection rates have improved compared to previous decades, or are there environmental influences that could be causing an increase? Or other factors?

  • Glad you are finding this tutorial helpful!

  • Interesting question - I think the rarity of cancer in this particular demographic probably means that clinicians are less likely to suspect it than say in someone who had smoked 30 cigarettes a day for 40 years. And therefore referrals tend to not be done so readily.

  • Great to see who you all are - keep the introductions coming! We'll be moderating the current week so if you are joining in a little later feel free to post any questions in the current week comments threads rather than in the earlier weeks. And please do answer each others questions as well - the more interactions the better!

  • Is it this article you are looking for?


    (not sure if its visible outwith a paywall....)

  • Sounds interesting - do you have any good links you could post relating to your work?

  • Yes it's definitely a lot to take in but hopefully the transcript (and the glossary in week 1) will help! Feel free to ask here if anything is confusing!

  • Yes sorry about that, it's because Louise has changed role since this course was made.

  • Yes - shes' one of the staff at NHSGGC - they don't have individual pages but this is the closest thing!

  • Glad you found it helpful Samantha, there's more from Karin in week 4.

  • Glad to see you are finding this a useful video - we often find it's very popular!

  • Hi, great to see you all here, thanks for introducing yourselves- keep the introductions coming. We realise that people will begin the course in their own time and it's always interesting for us to see who is here!

  • Sorry about that - maybe try opening on a different browser?

  • Not totally sure what you're asking - can you clarify and I'll try to answer?

  • Glad that week 1 was helpful and I hope you find week 2 as interesting!!

  • In brief you very possibly wouldn't. See https://firstaidcalgary.ca/how-to-perform-cpr-and-use-aed-on-an-individual-with-a-pacemaker/ for more information

  • Yes of course - glad you found it helpful!

  • Good point - thanks for mentioning that :-)

  • Thanks for pointing that out - I've updated the link

  • Welcome to everyone! And don't worry if you're starting the course a bit late, feel free to introduce yourself here!

  • Yes you're right it's available in the UK.

  • Thanks for that!

  • It tends to be that in a patient the cancer will either express or not express a particular protein - although you may get cells that don't which will therefore be resistant to the treatment.

  • There's a bit more on this as we go though these next two weeks but basically, scientists are finding that cancers are characterised by their mutation 'signatures'. These are basically groups of genes that have been deregulated and are driving the cancer progression. Although there are many different signatures, these are found again and again in different...

  • Two separate tumours in the one patient can be separate primary tumours (i.e. not directly related to each other). Or they can, as you say, be that one has spread to the second location. I would imagine that the doctor/oncologist should be able to tell the difference in an individual patient.

  • Hi there,

    The difficulty with most markers is that unaffected individuals will still have (generally lower) levels of these in their blood, produced from normal cells. It may be that the tumour is producing higher levels than normal, tending to raise the levels in the blood of someone who is affected. So they are not totally specific for cancer. The key to...

  • That's a very good point - I will remember to add that in for future runs of the course.

  • Maybe something like our MSc in Clinical Pharmacology would be of interest to you?


  • Yes both animals and humans have stem cells - and yes most animals can get cancer too

  • It's an interesting question - here is an article which tackles the subject (it's not the most recent one but it is freely available to all)


  • Very topical question! Yes the ultimate goal would be to be able to detect cancer at a very early stage by a simple blood test. Looking for tiny amounts of mutated DNA which have got into the blood, this test has received a lot of media attention in the last week or so


  • The way in which cells stop growing due to contact with other cells is thought to be due to signalling by membrane proteins such as p27 cyclin-dependent kinase inhibitor. This protein can bind cyclin-CDK complexes and this causes the cell to arrest its growth.

  • Here's a summary of some work relevant to this question (and some links to the original studies)


  • Have a look at the links at the bottom of the page - they're very good. If it's still not clear feel free to ask any questions you have!

  • Hopefully that will become clearer as we go through the week!

  • I know - the terms can be like a different language sometimes! Remember the link to the glossary is at the bottom of each step.

  • Glad you are finding it useful!

  • 60% of cases of retinoblastoma arise because an individual has by chance had a sporadic mutation in both copies of the Rb gene in the one cell. It's rare for this to occur but when you think of how many cells we have, an the number of cell divisions that occur, its not surprising that it happens sometimes.
    In the 40% of individuals who have the inherited...

  • Good point about the incidence - I think its currently somewhere between 1/2 and 1/3

  • The autosomes are basically all the chromosomes except the sex chromosomes (X and Y). You can read more about them here

  • Don't worry if you feel it takes a while to assimilate it all - we will be re-visiting some of the concepts as we go through the course.

  • Yes I would imagine that it does - we tend to have chaplaincies (for people of any or no faith) in all of our hospitals.

  • Nice to see a variety of backgrounds here - keep the introductions coming!

  • Don't worry there are quizzes as well and these should be available throughout - its just the end of week tests that are the 'paid for' add ons.

  • Yes you're right RE plant sciences - I think sometimes other areas can seem to have more publicity in some ways and we forget the huge contribution that plant science has to make - and also how it links to a whole range of other disciplines.

  • No limits on age :-) And indeed the greater diversity of learners the better!

  • It's hopefully going to give everyone a taste both for what life science is but also what it would be like to study it at university - including whether it's the right choice for you, applying, making the most of your time there and what you might do next.

  • Nice to hear where you're all coming from - keep posting!

  • Well spotted - thanks!

  • If you Google 'protocol for isolating macrophages' this seemed to bring up a number of relevant articles.

  • Interesting - what if a person with a family history decided they'd rather not know? Would it be ethical to screen them?

  • Not quite sure what you mean - there are some symptoms more typically associated with some cancers e.g. a cough could be associated with lung cancer whereas weight loss could be associated with one of several different types.

  • Interesting point to raise - what do others think about possibly testing the 7 year old?

  • Interesting post - might be useful for others to have the link to the recent study if you have it?

  • It's now available again!

  • I hope you enjoy the week!