Saturday, December 15, 2007

Kaposi’s Sarcoma and the Virus/Cancer Connection (Part 1)

Is cancer a contagious disease? The simple answer to that question is “No.” At least, that’s what we tell people. You can’t catch cancer from someone who has it. If a cancer patient is isolated, it’s to protect the patient from us, not the other way around. But, as is often the case, the truth is not quite so simple.

Let’s take a trip back in time. It’s 1984. Arguments rage about what to call the newly discovered virus that seems to cause this new disease called Acquired Immune Deficiency Syndrome (the American group proposed calling the virus HTLV-III while their French competitors wanted to call it LAV). When the dust settles, the virus is called HIV, and it quickly becomes clear that infection with HIV is not the same thing as having AIDS. So how do we define AIDS? Well, a person has AIDS if s/he is infected with HIV and has one of the so-called “AIDS Defining Illnesses.” Interestingly, one of these is a kind of cancer called Kaposi’s Sarcoma. Kaposi's Sarcoma causes nodules or blotches that may be red, purple, brown, or black. They are typically found on the skin, but spread elsewhere is common, especially the mouth, gastrointestinal tract and respiratory tract. Growth can range from very slow to explosively fast, and may be fatal.



All of the other AIDS defining illnesses, however, are infections that usually strike people with weakened immune systems (like cancer patients). So what is Kaposi’s Sarcoma doing on the list?

That question remained a mystery for quite a while. After all, although Kaposi’s Sarcoma was first described in 1872, it was originally known as a disease that affected older men from the Mediterranean region or who were of Ashkenazi Jewish descent. Yet, these men didn’t have AIDS, and no one knew why Kaposi’s sarcoma seemed to disproportionately affect this population. There is also a form of Kaposi’s Sarcoma endemic to sub-Saharan Africa, and although HIV infection is prevalent there now, that was not the case when endemic Kaposi’s Sarcoma was first described.

An answer to this mystery became apparent in 1994 when a group at Columbia University showed that Kaposi’s Sarcoma is actually caused by a virus. Originally they called it Kaposi’s Sarcoma Herpes Virus (because it is closely related to the viruses that cause herpes), but is has since been renamed HHV-8 (human herpesvirus 8). Subsequent work has shown that all forms of Kaposi’s Sarcoma are associated with an HHV-8 infection.

Over the years since the beginning of the AIDS epidemic, we have gotten pretty good at treating HIV infection, and with HAART (highly active anti-retroviral therapy), HIV infection has morphed from a rapidly fatal infection to a chronic disease. A by-product of the advent of HAART was the apparent disappearance of Kaposi’s Sarcoma. What was once an AIDS-defining illness, affecting as many as 80% of AIDS patients, there have been very few cases in the past 10 years.

Until now.

15 Kaposi’s Sarcoma cases were recently identified by doctors at San Francisco General Hospital. Surprisingly, these cases occurred in patients whose HIV infections were well controlled on HAART. This has prompted speculation about what happens as the immune system ages. These men all have undetectable HIV levels and normal numbers of white blood cells. Of course, so do the Ashkenazi Jewish men who used to be the primary group of KS patients. So what does this mean? Right now, no one is certain. But like all medical mysteries, we will all be a lot smarter once we figure it out.

5 comments:

Anonymous said...

Hi Dr. Loeb,
I've been following your blog, have you seen this PBS program,Secrets Of The Dead: The Black Death? I found the connection between the black plaque and HIV very interesting.
Antjude to C. Riley

http://www.pbs.org/wnet/secrets/case_plague/

DermDoc said...

Interesting and a bit disconcerting. I've only seen KS in HIV patients with abysmal CD4 counts; we often think that the most important treatment for KS in these patients is antiretrovirals.

Do you think this will become more of a issue as many HIV patients age with their disease?

Doctor David said...

It's hard to say... I have to admit I don't fully understand why these populations are subject to KS, because it isn't clear to me what they have in common. Unless the weakening of the aging immune system mimics loss of T cell function more similarly than we used to believe. But yes, I would worry that as HIV becomes a chronic disease and patients age, KS may become more common again. I think one lesson of viral oncology is that two components are necessary to contract a virus-mediated cancer: encounter with the virus and a host factor of some sort (immune deficiency, the wrong HLA type, or something else). Figuring out what the host factor is will become critically important as the HIV population ages.

Mrs. C said...

Dr. David, I'm a 66-yr.-old Sephardic Jewish woman with a non-HIV Classic or Mediterranean Kaposi on the bottom of my left foot, and in otherwise good health. Living in a rural area, it took two different clinics (and several head-scratching doctors) a couple of months before it got biopsied, and another month to see a dermatologist in a nearby city. It was a 1/4" round, dark purple spot. In the course of waiting for paperwork to get transferred, I took matters into my own hands and went to my local pot store (WA) and asked for a cannabis oil similar to RSO oil that I'd heard about. After a week of applying the oil, the dark area was a quarter of its original size. After another week, the color was completely gone and the area looks as normal as the skin around it. Unfortunately, the dermatologist also spotted and biopsied two other sites (on either side of my right knee) which tested positive for KS. While I await my appointment with a cancer clinic in Seattle, I'm going to pick up some more oil and apply it to the two new sites. I've been reading a lot about studies on the effect of cannabinoids on KS and there seems to be promise there.

Anonymous said...

I am HIV since about 1994 I started treatment on 2000 and 2004 I was fine my doctor suggested to stop for a while, I did stop and the first few years I check myself after a while I dint check myself, I was eating healthy socially drinking never smoke, I never have any health issues
Last year 2015 around Thanksgiving got some spots on my upper left leg went to the hospital
I thought it was a blood clog and they told me it was not they did an ultrasound and blame the swelling on my leg was a Baker's Cyst, the spots got a little bigger
I went to dermatologist on December 2015 he told me it was KS he suggested to get HIV medication, I went to an HIV clinic they put me Truvada and Prezcobix
I been taking this pills for almost 3 month and I don't see any progress it gets worse and bigger on top of that my leg swells a lot I can hardly work or walk, I have research all over the internet and there is nothing that tells how long it will take for this pills to work everything is about the virus nothing about the healing processes is very frustrating I asked my doctor if I should do chemotherapy or surgery and she said is to small of a section
I don't know when the pills are going to star doing something in the meantime this swelling and itching and hurting is so frustrating
Any suggestion or recommendation on what to do other then wait or a website with information about the process of healing not just about the virus?

Thanks!