Immunotherapy: awakening the immune system to fight cancer

Biomedical Sciences, cancer, Immunology

By Ross Keller, PhD candidate in Biomedical Science.

What is the immune system?

The human body is continuously under assault from a wide array of things that would do it harm. Many of these come in the form of pathogens—or microbes that infect the body and are not part of the body’s flora. These microbes range from common cold viruses to pneumococcal bacteria to deadly viruses like Ebola.


Immune cells attack a tumor cell (spiky cell in center). (Wikipedia)

However, the body can also come under attack from itself in a number of ways. One manner this occurs is when normal cells transform and begin dividing uncontrollably. Over time the rogue cells begin invading organs and destroying their normal function—this is known as cancer.

But, the human body has been evolving for millions of years, and over that time it has developed an extensive and complex defense system to ward off outside invaders like pneumonia as well as home-grown usurpers like cancer. It is termed the immune system.

The immune system is a complex network of non-specialized and specialized cells that each have a role in keeping the body safe. It can be divided into two broad categories: innate and adaptive. The innate immune system is the body’s way of attacking pathogens in a generic way, meaning many types of invaders will be treated equally—it acts fast. On the other hand, the adaptive immune system is composed of specialized cells that remember the specific type of invader and mount a specific attack when the invader is encountered a second time—it acts slowly the first time and quickly the second.

What is the immune system’s role in cancer?


Melanoma cells dividing rapidly. (Wikipedia)

The immune system is generally considered to have three main roles in preventing cancer— two indirect, and one direct. The first is to eliminate viruses, several of which have been linked to an increased risk for cancer. The second is to clear pathogens quickly to eliminate any inflammation that could produce an environment beneficial to a tumor. The third involves a direct way that the immune system protects from cancer, and that is called “immune surveillance.” (1).

Normal cells have receptors on their surface that the immune system recognizes—it’s a way that the cell can tell the immune system that it is “self” and supposed to be there. But, something happens when a cell’s genetic material begins to change, leading to the beginnings of cancer. The change in genetic material puts the cell under stress, and as a result, it begins to express receptors that are abnormal. The immune system can see these too, and in turn, it eliminates the precancerous cells. It’s the body’s way of recognizing a cancer cell before it begins to grow—or the body’s “surveillance” of the potential cancer.

How does cancer outsmart the immune system?

But, cancer does happen, which means cancer can sometimes outsmart and evade the immune system. The process is Darwinian in nature, meaning the cancer cells evolve and certain genetic changes are selected that grow out. One such adaptation that can cause a cancer to grow out is a genetic change that makes the precancerous cell “invisible” to the immune system. A way this happens is some cancer cells start expressing a receptor called PD-L1.


Receptors sit on the cell surface. They are used by the immune system to identify cells of the body and potential intruders. (Pixabay)

PD-L1 is a protein that sits on the cell’s surface. The way PD-L1 works is it recognizes a protein on the surface of an immune cell and tells the immune cell to “halt.” This stops the immune cell from killing the cell that expresses PD-L1.

In normal cells, it is a way the body stops the immune system from attacking itself. During events such as pregnancy, the body needs a fail-safe to keep the immune system from destroying newly formed tissue. It is also a check on auto-immunity. The body upregulates these proteins in select tissues when the immune system is overactive, such as with Lupus, or hepatitis (2).

But, cancers find a way to co-opt this mechanism of avoidance. During evolution, the cancer cells that express the PD-L1 protein are favored, and they continue to divide, meaning the whole tumor has now found a way to outsmart the immune system. The tumor tells the immune cells that are supposed to kill it to “halt,” and the immune cells listen, allowing the cancer to grow.

Can it be reversed?

There is a new wave of drugs being developed to harness the power of the immune system to treat cancer. One way is using drugs to block the interaction of the PD-L1 protein with the immune cells. The effect of this is stopping the cancer from being able to tell the immune system to “halt,” which means the immune system is now free to attack one the tumor once again.


President Jimmy Carter (right) pictured with Presidents Obama and Clinton. President Carter underwent treatment with Keytruda at age 90. (Wikimedia Commons)

So far, the drugs have shown promise. One drug, Keytruda (pembrolizumab), targets the PD-L1-immune cell interaction (3). It received recognition in the news because it was the treatment President Jimmy Carter received to treat his advanced melanoma, which had spread to the brain. Using more conventional therapies, the outlook for melanoma that had spread to the brain was bleak, but many patients, including the former President have responded well and remain in remission today.

Immunotherapy is a new frontier in the fight against cancer. New methods of immunotherapy are being developed all the time, including engineering “super immune cells” that fight specific cancers for specific patients. More on those in a later post.


  1. Swann, Jeremy B., and Mark J. Smyth. “Immune surveillance of tumors.”The Journal of clinical investigation5 (2007): 1137-1146.
  1. Chemnitz, Jens M., et al. “SHP-1 and SHP-2 associate with immunoreceptor tyrosine-based switch motif of programmed death 1 upon primary human T cell stimulation, but only receptor ligation prevents T cell activation.”The Journal of Immunology 2 (2004): 945-954.
  1. Burns, Michael C., Aidan O’donnell, and Igor Puzanov. “Pembrolizumab for the treatment of advanced melanoma.”Expert Opinion on Orphan Drugs just-accepted (2016).

The Bacteria that Mold Your Brain

Microbiology, Neuroscience

By Daniel Hass, 4th year Neuroscience PhD student

“Tell me what you eat, and I will tell you what you are”

This phrase, coined by Jean Anthelme Brillat-Savarin in the Physiologie du goût (The Physiology of Taste) was over a century ahead of its time.

Food Cheese

Some foods are better by virtue of their microbes. Cheese is one such food, matured by several types of bacteria (Wikimedia)

The commonly held aphorism is true in more ways than one. In one respect, it means that ‘the food you eat becomes a part of your person’,and this has long been known—amino acids from digested proteins are incorporated into our own proteins, and the energetic sources from our diet, such as sugars or fatty acids, are added to our own stores of energy. In another respect, the quote can mean that the food you eat influences ‘who’, or ‘what kind of person’ you are. This interpretation is also true– the substances you consume can alter your brain chemistry, and thus behavior (‘who’ you are), in manners too complex for a single blog post.

I will discuss the ways in which food affects our brains in a four-part series. Each part will examine a critical substance in food (microorganisms, carbohydrates, fats, and proteins) and the ways in which it alters or is central to behavior.

This first of these parts concerns a fascinating route by which diet can change the brain, and that is through our microbiome, the ecosystem of microorganisms such as bacteria, archaea, protozoa, fungi, and viruses that live on and interact with our bodies. Each adult has about 1 kg of these microbes, which are highly diverse, cumulatively containing approximately 100 times as many genes as the human genome.

The diversity and composition of these microbes in the gut is strongly influenced by diet.

Meet a Scientist: Our New Editor-in-Chief, Ross Keller

Biomedical Sciences

A note from our Editor-in-Chief: 

I will be defending my dissertation in just a few weeks, and therefore it’s time to hand over the reins. I would like to introduce Ross Keller, our new Editor-in-Chief! Ross is a 5th-year Biomedical Sciences graduate student, and he’s written and edited many blog posts that have been submitted to Lions Talk Science over the last three years. I have no doubt that the blog is in great hands! It has been amazing to watch this blog thrive since its launch in May 2013, and I can’t wait to see what’s next. Thanks for supporting our graduate student blog!

-Jordan Gaines Lewis

Now let’s get to know Ross!

Let’s get to know you a bit! Where are you from, where did you go to school, and what is your role at Penn State College of Medicine?ross

I grew up in Fargo, ND and attended West Fargo High School. I graduated in 2007 and went on to attend St. Olaf College in Northfield, MN. I graduated from there in 2011 and made my way to Penn State College of Medicine. I am now a PhD candidate in Biomedical Sciences focusing on cancer research, specifically novel mechanisms of initiation and modes to relapse using breast cancer models. In addition to research, I have served as the Social Chair, Community Service Chair and President of the Graduate Student Association. I have also been an editor at Lions Talk Science for three years and written several articles about cancer, genetics, and animal research. I’m thrilled to be the new Editor-in-Chief.

Going Viral: How Social Media Mirrors Science

Biomedical Sciences

By: Jillian Carmichael, 4th year student in the Biomedical Sciences Graduate Program



“Did you see that post? It’s going viral!”

Social media can be a strange beast. Within hours, funny videos about pandas going down slides or kids saying the most ridiculous things are all over the Internet. These viral posts saturate social media and it’s almost impossible to avoid seeing them (or at least hearing about them).

It’s curious how someone can go from complete Internet obscurity to “famous” within hours of posting content on social media. Considering the billions of social media posts made each day, how do certain posts rocket to viral status while most remain unremarkable? It takes the perfect combination of good timing, interesting content, the right audience, and plain old luck for a post to go viral.

Implicit in the terminology “going viral” is the concept of infectivity. In order for a social media post to reach viral status, it must spread quickly and extensively. In fact, a social media post going viral is very similar to how an actual virus can cause an epidemic.

Pregnancy Brain: A Neuroscientific Guide for the Expectant Mom (Part 2 of 2)


By: Jordan Gaines Lewis, 5th year student in the Neuroscience Graduate Program


Pickles and ice cream, anyone? (Shutterstock)

My forgetful friend – the subject of my original article – gave birth to a baby girl on Thanksgiving Day. She’s a beauty, and I know Mom agrees that the morning sickness, crazy sense of smell, and forgetfulness were worth it in the end.

In the meantime, while she’s experiencing a whole new set of biochemical processes that happens when a woman becomes a mother, let’s re-explore even more crazy changes that affect – or originate in – the brain during pregnancy. What causes clumsiness, food cravings, and moodiness?

Pregnancy Brain: A Neuroscientific Guide for the Expectant Mom (Part 1 of 2)


By: Jordan Gaines Lewis, 5th year student in the Neuroscience Graduate Program



A few months ago, my friend asked me, “Why have I become so forgetful since I became pregnant?” I told her I didn’t know, but that I’d look into it and write an article for her.

She then followed with, “I was going to ask you to explain something else to me, but I totally forgot what it was.”

Does “pregnancy brain” actually exist? There’s no doubt that many changes are happening to a woman’s body during pregnancy, but how do these changes affect (or originate in) the brain? To answer my friend’s question – and in an effort to address whatever else she was forgetting at the time – here is Part 1 of my expectant mom’s guide to the crazy neuroscience of pregnancy.

Zika Virus: The New Kid on the Block

Biomedical Sciences

By: Jillian Carmichael, 4th year student in the Biomedical Sciences Graduate Program


Aedes aegypti, the mosquito species currently responsible for transmission of Zika virus. (Source: Rafaelgilo/Wikimedia Commons)

Move over Ebola. There’s a new virus in town.

If you’ve been paying attention to the news in the past few weeks, you may have heard about the Zika virus outbreak that’s currently sweeping through the Americas. As with any emerging outbreak, fear is a common reaction in many people — remember how many Americans were terrified they were going to catch Ebola, even though they had never been to West Africa?

One of the best antidotes to fear is information — the better we understand a virus, the more equipped we are to deal with the outbreak and react in an appropriate manner.

In order to dispel any panic due to the fear-mongering media, I’ve compiled a list to answer some of the frequently asked questions concerning the Zika virus outbreak.

Meet a Scientist: Jessica Parascando

Graduate School

This is the eighth post in our “Meet a Scientist” series. Next up is Jessica Parascando, a 1st-year student in the Public Health program.

Meet Jessica:


Meet Jessica!

Let’s get to know you a bit! Where are you from, what did you study in college, and what is your role at Penn State College of Medicine?

I was born and raised in Edison, New Jersey, and lived there until I moved to Hershey in August. I received my BA in Psychology at Ramapo College of NJ, and then took post-baccalaureate courses in Biology and Statistics at Rutgers University, where I also worked in an Infant Neuroscience Laboratory.

I am currently a first year graduate student in the Master of Public Health program studying Biostatistics and Epidemiology.

Why did you decide to become a scientist?

My initial interest in science and sleep research began after watching an episode of the television show, Boy Meets World. In the episode, a character volunteered to participate in a study that was analyzing brain activity during sleep.

After seeing the research coordinator become perplexed at the character’s lack of neural activity during the session, I immediately became interested in how and why the brain works the way it does. There is still so much unknown about the exact function of sleep, so my goal is to combine my passions of neuropsychology and public health to help make the public more aware of positive sleep practices, and emphasize the importance of sleep at all ages.

What do you research at Penn State, and why is it important?

BabyLab 2I am currently working with a great team in a neuropsychology/biofeedback performance laboratory in the Psychiatry department. We use functional near-infrared spectroscopy (fNIR), electromyography (EMG) and ecological momentary assessments (EMA) to study patients with opiate addiction in hopes of identifying factors that may be associated with an increased risk of relapse during various stages of recovery.

This research is important because there is a worldwide epidemic of addiction, and relapse rates are extremely high for those who do seek recovery. We also collect sleep data using actigraphy, further emphasizing the relevance of sleep in all aspects of health.

What are some of your hobbies outside the lab?

Outside of the lab I am on the e-board for Public Health Association for Service and Education (PHASE). In PHASE, we promote public health awareness through various events on campus and in the central PA community. I also enjoy Pilates, random hikes, watching New Girl and other shows on Netflix, reading random science articles from Twitter, daydreaming, and spending time with friends.

Tell us three random facts about yourself!

  1. I’m obsessed with tea and drink it everyday. My favorites are Moroccan mint, oolong and toasted walnut.
  2. I have a Cockapoo named Kapoosta.
  3. I share Ron Swanson and Leslie Knope’s love of breakfast foods.

Stay tuned for future interviews! And if you’re a Penn State College of Medicine scientist interested in participating, e-mail for details!

What is Déjà Vu?


By: Jordan Gaines Lewis, 5th year student in the Neuroscience Graduate Program


Erika Wittlieb (Pixabay)

What is déjà vu?  Many of us know the feeling. You’ll be going about your day, minding your own business, folding some laundry…nothing out of the ordinary.

Suddenly a sensation of familiarity washes over you, and you’re completely aware that it’s happening. I’ve been here before. Except you haven’t. Or have I? You might try to think back and pinpoint when you’d experienced this moment before. But just as quickly as the feeling hits you, it’s gone again.

Did you predict the future? Were you seeing something from a past life? What is déjà vu, anyway?

Frankenfood? The Real Science Behind GMOs

Biomedical Sciences

By: Ross Keller, 5th year student in the Biomedical Sciences Graduate Program


Image source: Sam Fentress (Wikimedia Commons)

A recurring theme in science fiction is the ability to modify an organism’s genetic material. The goal is usually to give the modified person or creature amazing characteristics — super speed, super strength, or mind control, to name a few.

I haven’t met anyone with these features yet, but the future is already here. Scientists can modify the genomes of animals and plants with ease, though for an entirely different reason. You may be familiar with the term already: “GMOs.”

A genetically modified organism (GMO) is any living thing that has had its genome (its genetic material) modified. In general, GMOs fall into two major categories—organisms modified for research purposes and those modified for consumption.

You may be familiar with the advocacy work of the Non-GMO Project, Chipotle’s new G-M-Over It campaign, or seen social media postings from friends and family about the dangers of GMO food. But what’s the real science behind the science fiction?