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Showing posts with label Cancer. Show all posts
Showing posts with label Cancer. Show all posts

Wednesday 21 October 2015

Correcting DNA mistakes

Using the knowledge of how the cell repair systems work will open the door to more effective cancer treatments



UNDERSTANDING how our cells repair damaged DNA, a breakthrough which earned the Nobel Chemistry Prize recently, could make cancer treatment more effective, experts say.

By revealing how our cells automatically fix DNA mutations which can lead to illness, the discovery opened the door to significantly improving chemotherapy’s effectiveness against cancer, which kills some eight million people worldwide each year.

“You can use this knowledge to destroy cancer,” said Nora Goosen, a DNA repair expert at Leiden University in the Netherlands.

Chemotherapy attacks cancer cells by trying to scramble their genetic code and thus their ability to multiply, but cancer cells, just like healthy ones, do not give up without a fight.

he cell repair systems are going to try to undo the work of doctors by fixing the damage the doctors were trying to inflict,” said Terence Strick, a DNA repair researcher at the Jacques Monod Institute in Paris.

One solution would be to inhibit the ability of cancerous cells to self-mend.

“If you attack these repair mechanisms (in cancer cells) in combination with chemotherapy and other drugs ... it (treatment) can be more effective,” Goosen said.

Sweden’s Tomas Lindahl, Paul Modrich of the United States and Turkish-American Aziz Sancar were awarded the top chemistry award for unravelling the process by which our cells repair mutations caused to DNA by the Sun or carcinogenic substances found in alcohol and cigarettes, for example.

Mistakes in DNA, the chemical code for making and sustaining life, can cause cells to malfunction, age prematurely, and become cancerous.

The vast majority of changes to our DNA are immediately corrected, but some accumulate and lead to cancer. Some people are more susceptible to cancer because their DNA repair response is faulty.

Ironically, the same repair mechanism identified by the Nobel laureates can also cause cancerous cells to resist the effects of cancer treatment.

Alan Worsley, a spokesman for the charity Cancer Research UK, said new drugs are being developed to fight the disease.

He cited the treatment olaparib, which stops cancer cells from fixing DNA damage. It was approved by the European Commission in December 2014 for use in Europe.

Alain Sarasin of France’s CNRS research institute highlighted the risks of interfering with DNA repair systems.

“We don’t yet know how to target tumour cells specifically. If we gave a patient a molecule which inhibits the self-repair mechanism of cancer cells, it may also inhibit the repair systems of other cells like white blood cells,” he said.

“If, one day, we have a molecule which reinforces the DNA repair and can be targeted to blood cells, for example, followed by chemotherapy after, this would allow us to increase the chemotherapy dosage without unintentionally killing blood cells.

“For now, we don’t know how to do that.” – AFP

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Wednesday 20 October 2010

Prostate Cancer Symptoms, Treatment & PSA Tests; Couples counseling improves sexual intimacy after prostate treatment




Prostate Cancer Symptoms and Treatment

By LiveScience Staff

Prostate cancer is diagnosed in about 20 percent of men. It may be more prevalent, however, because some men never know they have it and die of other causes before the slow-growing cancer becomes a problem. 
Prostate cancer is the most common type of cancer found in American men, after skin cancer, according to the American Cancer Society. And prostate cancer is the second leading cause of cancer death in men, after lung cancer.

Only men have a prostate gland, which is just below the bladder, in front of the rectum. It is about the size of a walnut.

The prostate grows from birth to adulthood. But in some men, it keeps growing. This can lead to an enlarged prostate, a non-cancerous condition called benign prostatic hyperplasia (BPH).  This can cause problems passing urine.

In some cases, certain cells in the prostate become cancerous and continue multiplying.

Scientists don't know what causes prostate cancer, officially called prostate adenocarcinoma. Risk factors include smoking, age and family history.  A diet high in red meat also plays a role, studies suggest. Black men are more likely to get prostate cancer than others.

Experts don't agree on whether all men should be routinely tested for prostate cancer. One test involves the doctor putting a gloved finger in the rectum to feel for bumps or hard spots on the prostate. A blood test, called PSA (prostate-specific antigen) looks for signs of the disease in the blood.

"These tests are not perfect, though," states the American Cancer Society. "Uncertain or false test results could cause confusion and worry." And, the society notes, surgery is sometimes performed or radiation therapy conducted even when a doctor is not sure how fast the cancer might spread. Importantly, prostate cancer grows slowly, according to the American Cancer Society. In fact autopsies suggest that as many as 90 percent of men over age 80 have prostate cancer, most never knowing it and dying of something else.

"If you are older than age 70, you may opt for expectant management (also called watchful waiting) if your prostate cancer is growing slowly," according to the Mayo Clinic.

Early and accurate diagnosis of prostate can, however, improve odds of survival, studies show.

The American Cancer Society suggests the decision about whether to test should reside with patient and doctor after a discussion about the cancer and its risks. The talk should take place at age 50 for men who are at average risk, at age 45 for men at high risk of getting prostate cancer (African American men and men who have a father, brother, or son found to have prostate cancer before age 65), and at age 40 for men with several family members who had prostate cancer at an early age.
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Prostate Cancer: PSA Test (Part 2)


-IMAGEALT-
A breast cancer cell seen through an electron microscope.
CREDIT: The National Cancer Institute.

This is the second part of a three-part series on the PSA test for prostate cancer.
 
Cancer of the prostate is one of the most common types of cancer among American men. More than 6 in 10 cases of prostate cancer cases occur in men 65 and older. Treatment for prostate cancer works best when the disease is found early.

Prostate-specific antigen (PSA) is a protein produced by the cells of the prostate gland. The PSA test measures the level of this protein in the blood. It can be detected at a low level in the blood of all adult men.

A fundamental problem with the PSA test is that, while elevated levels can indicate the presence of cancer, they can also be caused by other problems such as benign enlargement of the prostate that comes with age, infection, inflammation and seemingly trivial events such as ejaculation and a bowel movement.

Another major problem with the PSA test is defining what is “abnormal.” Older men usually have higher PSA measurements than younger men. African-Americans normally have slightly higher values than whites.

PSA test results are usually reported as nanograms of PSA per milliliter (ng/mL) of blood. In the past, most doctors considered PSA values below 4.0 ng/mL as normal. However, recent research found prostate cancer in men with PSA levels below 4.0 ng/mL

Some researchers have suggested lowering the PSA cutoff levels. For example, a number of studies have used cutoff levels of 2.5 or 3.0 ng/mL instead of  4.0 ng/mL.

Many doctors are now using the following ranges with some variation: 0 to 2.5 ng/mL is low, 2.6 to 10 ng/mL is slightly to moderately elevated, 10 to 19.9 ng/mL is moderately elevated, and 20 ng/mL or more is significantly elevated.

Because age is an important factor in increasing PSA levels, some doctors use age-adjusted PSA levels to determine when diagnostic tests are needed. When age-adjusted PSA levels are used, a different PSA level is defined as normal for each 10-year age group.

Doctors who use age-adjusted levels usually suggest that men younger than age 50 should have a PSA level below 2.4 ng/mL, while a PSA level up to 6.5 ng/mL would be considered normal for men in their 70s. Doctors do not agree about the accuracy and usefulness of age-adjusted PSA levels.

But there’s even more to make you nuts when you’re evaluating your PSA.

PSA is either free or attached to a protein molecule. If you have a benign prostate condition, there is more free PSA. Cancer produces more of the attached form. A free PSA test that indicates prostate cancer can lead to more testing, such as a biopsy.

PSA velocity is the change in PSA levels over time. A sharp rise in the PSA level may indicate a fast-growing cancer.

The relationship of the PSA level to prostate size is PSA density. An elevated PSA in a man with a very large prostate is not as alarming as a high PSA reading in someone with a small prostate.

Another problem with PSA are false test results.

If you have an elevated PSA but no cancer, you get what is called a false positive. This type of result can lead to medical procedures, anxiety, health risks and expense. Most men with an elevated PSA don’t have cancer.

When you have prostate cancer and your PSA test comes back in the normal range, you get a false negative. It’s important to understand that most prostate cancers are slow-growing; they can be around for many years before they cause symptoms.

Prostate Cancer: PSA Test (Part 3)

[This is the final part of a three-part series on the PSA test for prostate cancer.]

Cancer of the prostate is one of the most common types of cancer among American men. More than 6 in 10 cases of prostate cancer cases occur in men 65 and older. Treatment for prostate cancer works best when the disease is found early.

Prostate-specific antigen (PSA) is a protein produced by the cells of the prostate gland. The PSA test measures the level of this protein in the blood. It can be detected at a low level in the blood of all adult men.

A fundamental problem with the PSA test is that, while elevated levels can indicate the presence of cancer, they can also be caused by other problems such as benign enlargement of the prostate that comes with age, infection, inflammation and seemingly trivial events such as ejaculation and a bowel movement.

PSA test results are horribly confusing and often terrifying. In the first parts of this series, we discussed the sources of much of the confusion. In this column, we’ll address the primary question about PSA: Does it save lives?

The answer is: We don’t know. What’s worse is that we don’t know if PSA screening outweighs the risks of follow-up diagnostic tests and cancer treatments.

For example, prostate surgery can cause incontinence and erectile dysfunction. Even a  prostate biopsy has risks because it can cause bleeding and infection.

The PSA test can detect small tumors. However, finding a small tumor does not necessarily reduce a man’s chance of dying from prostate cancer. PSA testing may identify very slow-growing tumors that are unlikely to threaten a man’s life. Also, PSA testing may not help a man with a fast-growing or aggressive cancer that has already spread to other parts of his body before being detected.

So, what should a man do to protect himself from prostate cancer?

Some doctors encourage annual screenings for men older than age 50; others recommend against routine screening. However, most doctors and medical organizations agree that men should learn all they can about prostate cancer, so they can reach informed decisions.

My personal history with PSA tests is illustrative of many of the problems men face with this type of screening. I hope that sharing it will help.

I’m 69 years old. I’ve been having physical exams almost every year since I hit my 50s. These physicals included a PSA blood test and a digital rectal exam (DRE).  Until recently, all tests produced normal results.

My PSA was always around 1.5. Most doctors want your PSA to be under 4. (The numbers stand for nanograms of PSA per milliliter of blood.) And, my DREs found no irregularities, just some benign enlargement.

About three years ago, my family physician gave me a DRE and found nothing, but my PSA test came in at 2.97. My doctor told me to see a urologist for a follow-up exam because my PSA, while under 4, had increased.

The urologist did another DRE and ordered another PSA test. The test came in at 2.96. The urologist said that he thought 2.96 was my new PSA and that I should not worry about it.

Two years later, my PSA was still 2.96. Then, this year, it came in at 4.1.  My family physician sent me to a urologist.

Before I went to the urologist, I did some research and learned that something as seemingly insignificant as a bowel movement could affect a PSA test. I told the urologist that I recalled going to the bathroom just before having blood drawn. He thought that this BM could have affected the test.

Another DRE. Okay. Another blood test. The PSA was 3.3. The urologist said no biopsy was required. The increase from 2.96 to 3.3 was not a cause for concern.

What now? I’m tempted to forget about PSA tests, but I’ll probably have another in a year.
The Healthy Geezer column publishes each Monday on LiveScience. If you would like to ask a question, please write fred@healthygeezer.com. © 2010 by Fred Cicetti.

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Couples counseling improves sexual intimacy after prostate treatment

September 25, 2011
Couples counseling improves sexual intimacy after prostate treatmentEnlarge

This is Leslie Schover, Ph.D, a professor in MD Anderson's Department of Behavioral Science. Credit: Image courtesy of MD Anderson 

VIDEO: Hope for Restored Sexual Function for Prostate Cancer Patients and their Partners
VIDEO: Sexual Counseling for Couples after Prostate Cancer Treatment
PODCAST: Listen to expert Leslie Schover discuss results of face-to-face and internet-based counseling.

Prostate cancer survivors and their partners experience improved sexual satisfaction and function after couples counseling, according to research at The University of Texas MD Anderson Cancer Center. The article, published in the September issue of Cancer, a journal of the American Cancer Society, revealed both Internet-based sexual counseling and traditional sex therapy are equally effective in improving sexual outcomes. Couples on a waiting list for counseling did not improve.

Men experienced a marked improvement in their sexual function for up to one year, and women who started out with a improved significantly with counseling.

"We know that one of the crucial factors in a man's having a good sexual outcome after treatment is a partner who also wants their sex life to get better," said Leslie Schover, Ph.D, a professor in MD Anderson's Department of , lead investigator on the study and author of the paper, "A Randomized Trial of Internet-Based Versus Traditional Sexual Counseling for Couples After Localized ." "Women's issues such as ill health, post-menopausal and lack of desire for sex can be a major barrier in achieving satisfactory sexual outcomes."

Leslie Schover explains the significance of results in randomized trial incorporating couples counseling for prostate cancer patients and their partners. Credit: Video courtesy of MD Anderson

CAREss (Counseling About Regaining Erections and Sexual Satisfaction) randomized 115 heterosexual prostate cancer survivors who were experiencing erectile dysfunction and their partners into three groups: a wait list group that received delayed counseling, a face-to-face counseling group, and a group that received an Internet-based sexual counseling program.

After three months, the wait-list couples were randomized into either the face-to face or the Internet-based counseling group. A second Internet-based group of 71 couples was added to boost the numbers and allow researchers to analyze the relationship between extent of website use and outcomes.

Couples were assessed before and after the three-month wait-list period, again after counseling, and also at six and 12-month follow-ups. In addition to web-based education and exercises, participants in the Internet-based group received feedback from their counselor through email.

Treating the Body and the Mind

Many prostate cancer survivors are as concerned about loss of desire and lack of satisfying orgasms as they are about erectile dysfunction. Men in this study improved on most dimensions of sexual function. From baseline to one year, men improved significantly in erectile function, but also in orgasmic function, intercourse satisfaction and overall . Sexual desire remained stable.

Leslie Schover discusses results of face-to-face and internet-based counseling. Credit: MD Anderson

Some patients and/or partners are too anxious about sexual issues to seek help from a therapist face-to-face. An internet-based program that offers online tools and surveys, as well as interaction with the therapist by email, gives them a less threatening option. "Not only do men often use the internet to search for information on sex, but prostate cancer patients consider the web a valuable resource for information on the impact of treatment on sex," said Schover.

Another advantage of web-based counseling for couples is the potentially lower cost. While many insurance companies cover medical treatment of erection problems after , the cost of sex therapy is often not reimbursed. Already burdened with co-payments for their cancer treatment, many couples cannot afford additional costs associated with mental health care.

Thursday 5 August 2010

Potential Prostate Cancer Marker Discovered






Potential Prostate Cancer Marker Discovered

ScienceDaily (Aug. 2, 2010) — Studies by a Purdue University-led team have revealed a potential marker for prostate cancer that could be the starting point for less invasive testing and improved diagnosis of the disease.



Images from the desorption electrospray ionization mass spectrometry analysis of prostate tissue samples are shown next to stained slides of the same samples. The images show that cholesterol sulfate is present in cancerous tissue and precancerous legions called high grade prostatic intraepithelial neoplasia, or PIN. A Purdue University-led research team discovered that cholesterol sulfate is a potential marker for prostate cancer. (Credit: Demian Ifa/Purdue Center for Analytical Instrumentation Development)

The team used a new analysis technique to create a profile of the lipids, or fats, found in prostate tissue and discovered a molecular compound that appears to be useful in identifying cancerous and precancerous tissue. The profile revealed that cholesterol sulfate is a compound that is absent in healthy prostate tissue, but is a major fat found in prostate cancer tumors.

Graham Cooks, Purdue's Henry Bohn Hass Distinguished Professor of Chemistry, and Timothy Ratliff, the Robert Wallace Miller Director of the Purdue Center for Cancer Research, led the team.

"It was surprising to find a single compound that is distinctly present in cancerous tissue and not present in healthy tissue," said Cooks, who is co-director of Purdue's Center for Analytical Instrumentation Development. "We've been able to differentiate cancerous from healthy tissue using this new method in the past, but the difference was in the amounts of the same chemical compounds found in healthy tissue. There was no single differentiator of which one could say if it was present there was cancerous tissue."

Ratliff said this characteristic makes the compound a potential marker for the disease, which could lead to new blood or urine tests to screen for prostate cancer.

"Aside from skin cancer, prostate cancer is the most common cancer in men and is the second leading cause of cancer-related deaths," Ratliff said. "Unfortunately, the current screening test has a significant number of false positives because it uses a marker that is present with other non-cancerous conditions. As a result, many men have unnecessary biopsies, which are invasive, expensive and have the potential to cause infection. This new compound appears to be highly specific to prostate cancer cells, which would mean very few false positives."

The current prostate cancer test screens for a protein called prostate-specific antigen, or PSA, that is produced by the cells of the prostate. Elevated levels of PSA in the blood can signify prostate cancer, but non-cancerous conditions such as an enlarged or inflamed prostate also cause an increase in its levels, he said.



The findings of the study, which was funded by the Purdue University Center for Cancer Research and the National Institutes of Health, were published in the journal Analytical Chemistry.

The study was performed in collaboration with physician scientists from Indiana University School of Medicine, who co-authored the paper. They also provided the tissue samples and pathological analysis of the samples to check the new technique's results.

The team used a mass spectrometry analysis technique developed by Cooks and coworkers called desorption electrospray ionization, or DESI, to measure and compare the chemical characteristics of 68 samples of normal and cancerous prostate tissue.

Mass spectrometry works by first turning molecules into ions, or electrically charged versions of themselves, so that they can be identified by their mass. Conventional mass spectrometry requires chemical separations, manipulations of samples and containment in a vacuum chamber for ionization and analysis. The DESI technique eliminates these requirements by performing the ionization step in the air or directly on surfaces outside of the mass spectrometers, making the process much simpler, faster and more applicable to medical examination or surgical settings.

Cooks' research team also has developed software that turns the distribution and intensity of selected ions within a sample into a computer-generated image, much like what would be seen from a stained slide under the microscope. This chemical map of the sample can precisely show the location of cancerous tissue and the borders of tumors, Cooks said.

Livia Eberlin, co-author of the paper and a graduate student in Cooks' group, said the study showed promise in detecting precancerous lesions, as well.

"The DESI examination was able to distinguish a precancerous lesion in a small area of a sample made up of mostly healthy tissue," Eberlin said. "By evaluating the difference in the chemistry of cells, this technique can detect differences in diseased tissue that are otherwise indistinguishable. It could provide a new tool for pathologists to complement microscopic examination."

The team also plans to study differences in the chemistry of different types of prostate cancer tumors to see if there is a way to identify which are aggressive and which are not, she said.

Ratliff said the inability to tell the difference between aggressive and nonaggressive forms of prostate cancer causes problems in its treatment.

"A nonaggressive form of prostate cancer can be very slow to progress, and sometimes it is in the best interest of the patient not to go through rigorous treatments that reduce one's quality of life," he said. "The tests currently used to determine the probability that the cancer is an aggressive form are not very accurate, and about 30 percent of patients are misdiagnosed as having an aggressive form."

Additional co-authors of the paper include graduate students Allison Dill and Anthony Costa, and post doctoral researcher Demian Ifa from Purdue's Department of Chemistry and the Center for Analytical Instrumentation Development; Dr. Liang Cheng from the Indiana University School of Medicine Department of Pathology and Laboratory Medicine; and Dr. Timothy Masterson and Dr. Michael Koch from the Indiana University School of Medicine Department of Urology.

The team is already in the process of performing larger studies and plans to investigate the biological processes responsible for the expression of cholesterol sulfate in cancerous tissue.



Story Source:
The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Purdue University. The original article was written by Elizabeth K. Gardner.
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Wednesday 2 June 2010

Prostate Cancer Patients' Weight Linked to Tumor Size, Study Finds







ScienceDaily (June 2, 2010) The size of tumors in prostate cancer patients is directly linked to their weight, according to a new six-year study conducted by researchers at Henry Ford Hospital in Detroit.

The research team, led by Nilesh Patil, M.D., of Henry Ford's Vattikuti Urology Institute and Department of Radiology, found heavier patients, or those with the highest body mass index (BMI), also had the largest tumors. They discovered the connection after studying 3,327 patients who had undergone robotic removal of their cancerous prostate glands and surrounding tissue.

"As the patients body mass index increased, the tumor volume increased synchronously," says Dr. Patil. "Based on our results, we believe having a larger percentage of tumor volume may be contributing to the aggressive nature of the disease in men with a higher BMI."



The study will be presented June 2 at the 2010 American Urology Association's annual meeting in San Francisco.

Working from a well-established link between aggressive prostate cancer and higher BMI, the team set out to find if overweight and obesity specifically affects the tumor volume in cancerous prostates.

The BMI measures body fat based on combined height and weight in adult men and women, and sets a number that defines underweight, normal weight, overweight, and obesity -- from 18.5 or less for underweight to 30 or higher for obesity. Tumor volume is the size of a malignant tumor as a percentage of the space it takes up in the affected tissue, in this case the prostate gland.

Patients were studied from October 2001 to October 2007. They were divided into six categories based on their BMI -- 24.9 or less (normal or underweight), 25 to 29.9 (overweight), 30 to 34.9 (obese), and 40 or higher (morbidly obese). In each category, the mean age was about 60.

After their tumors were removed, each was weighed and compared to a categorized database of prostate weight. In each BMI category, they found the weight of the patient to be directly correlated to the size of the tumor (i.e. the smaller the patient, the smaller the tumor, and the heavier the patient, the larger the tumor).

In addition to Dr. Patil, study co-authors at Henry Ford Hospital included Sanjeev Kaul, M.D.; Akshay Bhandari, M.D.; James Peabody, M.D.; and Mani Menon, M.D.

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