Dr Momna Hejmadi

Dr Momna Hejmadi

A member of University of Bath’s cancer research group, Dr Momna Hejmadi has also received awards for excellence in teaching and has carried out work in open education resources.

Location Bath

Activity

  • I use it for my first year classes to Patricia - I absolutely agree - its a great website for beginners

  • Cancer cells 'release' factors (typically proteins such as Vascular Endothelial Growth Factor) that stimulate blood vessels to divide and expand the network of blood vessels inside the tumour.

  • Genomic imprinting is one mechanism in which epigenetic marks are inherited through one of the parental copies. Prof. Andrew Ward researches on genomic imprinting and its impact on development and disease https://researchportal.bath.ac.uk/en/persons/andrew-ward

  • thats correct, they do code for RNAs Reuben. Traditionally, coding typically refers to proteins (and for the purpose of this course)

  • you should have access to all 4 weeks Patricia, from what I understand. Please email the Futurelearn team if you dont get access to all 4 weeks.

  • Hi Phil. Introns are excised out and it is the exons that are spliced together that are then translated to make proteins. If the DNA (i.e. exons) have a mutation, it can change the type of protein made, which in turn MAY lead to abnormal proliferation.

  • many thanks for pointing this out Lily. The link is updated now.

  • Good to see the lively discussion here, and why it is indeed a case of natural selection. Interestingly, while the phenomenon was discovered a while ago, the gene mutation (gene called 'cortex') responsible was only discovered in 2016 by Illik Saccheri's group in Liverpool. It also has an unusual event that gave rise to the mutation. The original paper is here...

  • Hi Joseph. Certainly, the implication, if any, was unintentional.

  • they could still breed since the two colours of mice belong to the same species. Speciation occurs when breeding does not happen. If the two strains of mice breed, then the fur colour would vary depending on whether the offspring inherited the mutation that causes the change in colour. The human equivalent of the same gene, Mc1r, is the one that is linked to...

  • apologies about the volume, will try to re-record this for next time. However, the subtitle and video transcripts may help for this one

  • to add to Laurence's point, somatic cells have a higher mutation rate but cells also have very effective DNA repair mechanisms that usually 'fix' most mutations that arise through metabolic or replication errors.

  • but we do know Hind, each rung is a complete A=T or a C=G link. The Human Genome Project in 2000 mapped precisely that, and we know that within each nucleus of a typical human cell, there is 323,000,000,000 base pairs of DNA (or 'rungs' of the ladder)

  • certainly John. What would you suggest we could include in the future?

  • that is absolutely correct Steven

  • thank you very much for this feedback Kelly. I shall certainly be forwarding your comments on to our staff. I am also slightly surprised by this because we have a history of having mature students on our courses, many of whom have won prizes and gone on to do PhDs. Once again, thank you for your honest feedback, this really helps!

  • I am really sorry to hear that you are undergoing treatment for kidney cancer and I hope the treatment works. Unfortunately, kidney cancer is also called a 'silent' cancer because the symptoms -typically back ache and fever (which in the vast majority of people are not cancer-related) - usually occur only after the tumour has grown quite large and spread. You...

  • http://go.nature.com/2FsOnhL
    This Nature Community Hub blog post explores how host genetics, microbiome and environmental factors can influence a person's cancer-immune setpoint.

  • I will reply in the video Mari

  • The 2 processes may work in parallel, not necessarily in a linear order Kelly. E.g. in certain leukaemias, we now know that alterations in stem cell reprogramming (i.e. transcription factors) are key to the formation of aberrant blood stem cells. In other cases, such as colon cancers, this is less well documented, although we are now discovering mutations in...

  • The hallmark of EMT is the loss of epithelial surface markers, most notably E-cadherin, and the acquisition of mesenchymal markers including vimentin and N-cadherin. This is very well documented in the literature, Khem. Here is a link to one of them https://www.ncbi.nlm.nih.gov/pubmed/26905733

  • I was referring to chemotherapy Susan.

  • There are various classes of chemo drugs, each working in a different way. They do not trigger metastasis on their own.

  • its the tumour cells usually that secrete VEGF which binds to VEGF receptors found on the endothelial cells, which stimulates the endothelial cells to divide and form new vascular structures

  • Interesting point Karen. We do know that normal vascularisation is not evenly distributed in all organs equally though. For instance, kidneys, liver, colon are very highly vascularised (as you would expect for its function) but the brain has a protective blood brain barrier. Secondly, tumour vascularisation is highly disorganised and uneven, compared to normal...

  • my apologies, it is remnant from an earlier version of the course (which was longer). Do ignore the comment 'last week' - the narrative is still correct in that cell growth and division is part of normal function. Thanks for pointing this out

  • the organisation of a plant cell (thicker walls) is very different to an animal cell (thinner walls). Supply of oxygen and nutrients is via circulatory system in animals but through xylem / Phloem in plants. You might find this link below useful
    http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa_pre_2011/cells/cells1.shtml

  • Hi Khem and Kelly. You have picked up on a relatively poorly understood cancer group, leukaemias. ALL (acute lymphocytic Leukaemia) is relatively rare compared to the chronic version (CLL). ALL progresses much more rapid than CLL and is the most common type of leukaemias in children. CLL on the other hand, is more common in 60+ age group, and it progresses...

  • Thanks for pointing out the glossary issue everyone, we will try to fix it as soon as possible

  • Plant cells also develop tumours but are less frequent and less lethal than animal cells because of the typical plant cell wall structure. This is also the reason why metastasis (spread) does not occur in plants because plant cells do not tend to move around.

  • Hi Nicky
    I am not a clinical oncologist so I cannot comment on how human tumours look like, but have seen a lot of mouse tumours. It will depend on the type of tumour. For example - a melanoma on the skin shows up as a change in size, shape and colouration of a mole or wart. With internal tumours, such as colon carcinoma, it usually starts as polyps or a...

  • One can only REDUCE the RISK of developing cancer, not prevent it really. As I mentioned, one of the biggest risk factors is age, but diet and lifestyle can play a big part in reducing the risk. There are many public awareness campaigns in the UK (mainly through charities such as Cancer Research UK) which aim to inform the public of these risks.

  • Hi Linda
    One of your co-learners, Stephanie McLeod has provided a very useful link https://www.varian.com/en-gb/oncology/solutions/radiotherapy
    In brief, radiation can be given from sources outside the body as beams (External Beam radiotherapy) or inside the body through tiny radiation-emitting beads/seeds (brachytherapy). The choice depends on the tumour...

  • I would advise people to view websites promoting products that prevent cancer with the healthy criticality it deserves. Our diet and lifestyle can play a big part in REDUCING THE RISK but not preventing cancer development. The

  • that is correct Nicky, that cancer stem cells tend to be resistant to chemotherapy. This resistance also depends on the type of cancer stem cell (progenitor, pluripotent or multipotent) and also the tumour microenvironment which can protect the cancer stem cells from chemotherapeutic drugs. Here is a link you may find interesting to...

  • The normal job of a tumour suppressor gene product (i.e the protein) is to prevent cell division in times of DNA damage or stress to the cell (so that the cell has time to repair or fix this damage first before continuing through to division). Therefore the normal functioning tumour suppressor suppresses abnormal cell division (i.e. cancer). However, when the...

  • thats correct Janet, mutations or epigenetic changes alter the cell behaviour to make them either more likely to detach and spread through the blood and/or lymphatic systems.
    Interesting question about benign tumours. If a tumour is benign, these cells are no longer dividing (hence no increase in size or growth), then it is very unlikely that they will...

  • Hi Lyall
    The presence of stem cells or stem cell-like cells are now being discovered in more and more tissues of the human body. The normal role of stem cells is to either self-renew or progress into a differentiated cell type. As you mentioned the HSC (haematopoietic stem cells) in the bone marrow enable formation of different NORMAL blood cell types. What...

  • Hi Janet
    Almost all cells have the capacity to respond to various chemical signals. e.g. endocrine cells send hormones as chemical messengers (e.g. ovarian sex hormones such as estrogen) which can be picked up by target cells which express receptors for these hormones (such as estrogen receptors in the breast cells).

  • this is a really interesting question Karen, and an area on ongoing research. There are several models proposed, but one prevailing hypothesis is that cancer cells undergo at least two rounds of transitional cell type changes. Typically, if the cancer cells originate in epithelial tissues (as most common cancers are), they transform into mesenchymal cell...

  • i've answered this question that you posted in the earlier sections Gilberte :)

  • thats right, necrosis could be stress induced. E.g tissue injury due to frostbite