human metastatic breast cancer cells (from abcam.com)

Two recently published cancer studies reveal differences in the severity of cancer (specifically breast and colorectal) between black Americans and other racial or ethnic populations are based in genetic variations.  I think we should pause a moment and recognize that today is National Day, an observance popular in K-12 education to recognize the day that the research scientists at NIH completed sequencing of the human genome.  The knowledge gained from that tremendous endeavor has informed the physicians and scientists is countless labs since and the current findings in the disparities between the burden of illness suffered by blacks with breast or colorectal cancer tumors is no different.

Dr. Carol Rosenberg and her colleges at Boston University School of Medicine have discovered that cancer tumors lacking genetic expression for estrogen receptors, progesterone receptors and HER-2 (human epidermal growth factor), so called “triple-negative” tumors were more common among black women.  Specifically, their study of 415 women (36% non-Hispanic white, 43% black, 10% Hispanic, and 10% other) revealed that black women have a three times greater risk of having triple-negative breast cancer tumors as compared to non-Hispanic whites.  Triple-negative phenotype tumors (which make up 15% of all invasive breast cancers) have been associated with poor prognosis and low 5-year survival rates.  The implications are significant to understanding the prevalence of an increased burden of illness and death suffered by black women developing breast cancer.

“The reasons explaining this finding are not certain, but it is possible that black women may be at intrinsically greater risk of these more aggressive tumors,” observed Dr. Rosenberg.

The proportion of black women suffering from triple-negative breast cancer tumors was the same when comparing women under or exactly fifty years of age to those over fifty, as well as women who were obese to those who we not obese.  The findings of this study were release late last month in the Journal of Breast Cancer Research.

Earlier this month, Upender Manne, PhD and his colleges at University of Alabama at Birmingham released the results of their investigation of colorectal cancer in Clinical Cancer Research.  Scientists have thoroughly documented he p53 gene and its association with colon cancer in the literature.  In the current study, statistically significant differences in colorectal cancer tumors where identified and described.  Dr. Manne and his team reviewed 373 patients (63% non-Hispanic white and 37% black surgically treated between 1985 and 1995 at the anatomical, cellular and genetic level.  The codon 72 of the p53 protein can contain the amino acid (a protein building block) proline (Pro) or arginine (Arg).  As a result, there are three different phenotypes of p53 protein Arg/Arg, Arg/Pro or Pro/Pro.  In previous studies, researchers have found the Arg/Arg phenotype of the p53 protein to have a higher potential for inducing apoptosis (or programmed death of cancer cells).  On the other hand, the Pro/Pro phenotype of the protein has been found to accompany a greater proliferation of cancer cells.  In general, mutations that disrupted or inactivated the p53 protein have been associated with progression of the cancer.

The racial difference in the prevalence of these phenotypes of p53 protein associated with the colon cancer tumors was statistically significant.  Nineteen (19%) percent of colorectal cancer tumors in blacks had the Arg/Arg phenotype protein compared to 36% of the tumors in whites; 64% of tumors in blacks had the Arg/Pro phenotype protein compared to 57% of the tumors in whites; and 17% of tumors in black had the Pro/Pro phenotype protein compared to 7% of whites.  The implication of the numbers is this:

blacks had a higher prevalence of the p53 protein phenotype (Pro/Pro) which is associated with more aggressive tumors and progression of the cancer.

Specifically, this Pro/Pro phenotype was 2.5 times more likely to be associated with death in black patients than those with the other phenotypes.  In stark contrast, these Pro/Pro phenotye p53 proteins were only 1.6 times more likely to be associated with death in white patients than those with the other phenotypes.  As Dr. Manne stated,

“African-Americans, but not Caucasians, with the Pro/Pro phenotype had significantly higher mortality…and risk of death due to [colorectal cancer].”

This particular study, also identified additional, statistically significant

April 2009 issue

differences between tumors in blacks and non-Hispanic whites that create future opportunities to examine and disaggregate what Manne referred to as the “confounding from other lifestyle factors of the aggressiveness of the disease.”

Medscape Oncology contacted an independent physician, Dr. Hemant Roy of the Feinberg School of Medicine at Northwestern University to comment on the clinical significance of colorectal cancer study.  “Risk assessment is complex, and this and other genetic polymorphisms are an important piece of the puzzle…While this observation may not necessarily represent a stand-alone future test, it takes us closer to understanding risk and hence targeting screening.”  I think this observation speaks to the value of the molecular and genetic characterizations that come from health disparities research such as the two studies I discussed here, they decipher a piece of the entire puzzle that determine risk factors and help health care providers target and personalize the screening process.

Sources:

Stead LA, Lash TL, Sobieraj JE, Chi DD, Westrup JL, Charlot M, Blanchard RA, Lee JC, King TC, Rosenberg CL. Triple-negative breast cancers are increased in black women regardless of age or body mass index. Breast Cancer Res. 2009 Mar 25;11(2):R18.

Beals JK. New Polymorphisms Affect Colorectal Cancer Risk, Progression in
Blacks.  In Medscape Medical News.  Cited April 24, 2009.  Available at <http://www.medscape.com/viewarticle/590604>

Katkoori VR, Jia X, Shanmugam C, Wan W, Meleth S, Bumpers H, Grizzle WE, Manne U.  Prognostic significance of p53 codon 72 polymorphism differs with race in colorectal adenocarcinoma. Clin Cancer Res. 2009 Apr 1;15(7):2406-16.

The prevalence for different types of cancer varies greatly according to the race and ethnicity of the population in question.  For example:

• While the gap (as compared to non-Hispanic whites has narrowed since 1991) black Americans are more likely to develop and die from cancer than any other racial or ethnic group. The most common cancers among men in 2009 are projected to be prostate (34%), lung (16%), and colorectal (10%) cancer, and among women, breast (25%), lung (12%), and colorectal (11%) cancer. For all cancer types, blacks are far more likely to be diagnosed in advanced stages of disease, when the cancer is less treatable.  Blacks are also less likely than whites to survive 5 years after a diagnosis, regardless of cancer type and stage of diagnosis.
• Cancers associated with viral infection are the most common caners in Hispanics/Latinos. Women have the second highest number of cases of cervical cancer (which is often caused by human papillomavirus) while cases of liver cancer (which is often caused by the hepatitis virus) are twice as high in Hispanic men and women as in non-Hispanic whites.
• Asian Americans/Pacific Islanders are more likely to develop and die from both liver and stomach cancers than all other racial or ethnic groups (except in the case of stomach cancer where their prevalence and death rates are second to those of blacks).

Racial and ethnic minorities have less access to cancer screening

Medical researchers focusing on areas of health care disparities continue investigations to elucidate these figures. The interrelationship between multiple factors continues to yield reasons that are complex.

“Rates are driven by social and economic factors,” says Ahmedin Jemal, PhD, ACS Department of Epidemiology and Surveillance Research. “In the African American population, there’s far less utilization of screening. For example, in 2005, 44% of African Americans were screened for colorectal cancer, compared to 51% of whites.”

Other research reveals this failure to access care through regular recommended screening is true across all racial/ethnic minority groups. Surveys show that about a third of Hispanic/Latinos and 20% of blacks have no coverage at all. The consequences are significant as people who don’t get mammograms, colon exams, and Pap tests on schedule are more likely to be diagnosed with a cancer at a later stage in the disease, when survival rates are lower.

“Having health insurance coverage is the single greatest determinant of access to health care services,” explained Eve Nagler, ACS Director of Special Populations.

Access Resources:

Use this CDC interactive map to locate National Breast and Cervical Cancer Early Detection Program low-cost and free screening resources near you.

Sources:

Cancer’s Racial Gap Narrowing yet Challenges Persist. In ACS News Center. American Cancer Society.  Cited April 22, 2009. Available at <http://www.cancer.org/docroot/NWS/content/NWS_1_1x_Cancers_Racial_Gap_Narrowing_Yet_Challenges_Persist.asp>

Cancer Is A Burden, Finding Help Should Be. In In the Spotlight.  American Cancer Society. Cited April 22, 2009.  Available at <http://www.cancer.org/docroot/SPC/content/SPC_1_Cancer_Is_a_Burden_Finding_Help_Shouldnt_Be.asp>

Bridging the Disparity Gap.  In In the Spotlight.  American Cancer Society. Cited April 22, 2009.  Available at <http://www.cancer.org/docroot/SPC/SPC_0.0.asp>

Why is Diabetes Alert Day important?

• 23.6 million children and adults in the U.S. have diabetes
• Nearly one-quarter of those do not know they have diabetes
• One in five Americans is at risk for developing type II diabetes

For many, diagnosis may come seven to ten years after the onset of the disease. Therefore, early diagnosis is critical to successful treatment and delaying or preventing some of its complications such as heart disease, blindness, kidney disease, stroke, amputation and death.

Everyone should be aware of the risk factors for type 2 diabetes. People who are overweight, under active (living a sedentary lifestyle), and over the age of 45 should consider themselves at risk for the disease. African Americans, Latinos, Native Americans, and people who have a family history of the disease are at an increased risk for type II diabetes.

Watch this video to learn more.

Source: This post was a excerpt from: 21st Annual Diabetes Alert Day. In Community Programs and Local Events. Alexandria, VA: American Diabetes Association. [cited March 22, 2009] Available at <http://www.diabetes.org/communityprograms-and-localevents/ american-diabetes-alert.jsp?WTLPromo=FNLP_alert>

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In recognition of American Heart Month, this video recognizes the 2nd cause of death among American women. Stroke is a complication of cardiovascular disease, CVD (also known as heart disease). The NYTimes.com “Living with…” video chronicles strokes that resulted from heart disease brought on by years of obesity and Type II Diabetes. While heart attack and congestive heart failure affect the vessels of and ultimately the heart itself, stroke is a result of complications in the vessels that supply the brain instead. This results in localized damage to the brain. Unfortunately, many people still do not recognize the signs of a stroke and therefore delay urgently needed treatment. Because every second without treatment counts, learn these warning signs of stroke and teach them to others:

• Sudden numbness or weakness of the face, arm or leg, especially on one side of the body
• Sudden confusion, trouble speaking or understanding
• Sudden trouble seeing in one or both eyes
• Sudden trouble walking, dizziness, loss of balance or coordination
• Sudden, severe headache with no known cause

Watch Living with: Stroke

(videos are listed in reverse chronological order on the right, use mouse to highlight and select video titled “Living with: Stroke”, February 2009)

Sources: americanstrokeassociation.org and more about “NYTimes.com Living With: Stroke“, posted with vodpod

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National Black HIV/AIDS Awareness Day is directed, planned and organized by a working group of national organizations in partnership with the Centers for Disease Control and Prevention (CDC). The goal of this partnership is to to mobilize communities and address specific issues and best practices that are science-based and will influence the course of HIV in Black communities across our country.

According to the CDC, of all racial and ethnic groups in the United States, HIV and AIDS have hit Black Americans the hardest. Latest estimates from their 2006 HIV Incidence (number of new cases) Surveillance System confirms

…that blacks experienced a disproportionate number of HIV infections. Forty-six percent of new HIV infections occurred in blacks, even though blacks comprise only 12% of the US population. The majority (65%) of new infections in blacks occurred in men. Among black men, 63% of new infections occurred through male-to-male sexual contact. Thirty five percent of new infections in blacks occurred in women. Of those, eighty-three percent of the infections occurred through high-risk heterosexual contact. The disparity in new infections was especially pronounced among women, with the incidence rate in black women being almost 15 times higher than that of white women.

Black life is worth saving! Get Educated…

When we look at HIV/AIDS by race and ethnicity, we see that Black Americans have

• More illness. Even though all blacks account for about 13% of the United States population, we account for about half (49%) of the people who contract HIV and are diagnosed with AIDS.
• Shorter survival times. Blacks with AIDS often don’t live as long as people of other races and ethnic groups with AIDS. This is due to the barriers mentioned above.
• More deaths. For Black Americans, HIV/AIDS is a leading cause of death.

For Black men, the most common ways of contracting HIV (in order of frequency) are: having unprotected sex with another man who is HIV+ve, sharing injection drug works (like needles or syringes) with someone who is HIV+ve, and having unprotected sex with a woman who is HIV+ve. On the other hand, for Black women, the most common ways of contracting HIV (in order of frequency) are: having unprotected sex with a man who is HIV+ve and sharing injection drug works (like needles or syringes) with someone who is HIV+ve.

The segment of Blacks in America at highest risk for contracting HIV are those:

• who are unaware of their partner’s risk factors and/or HIV status
• with other STDs (which affect more Blacks than any other racial or ethnic group)
  
• who live in poverty (which is roughly one quarter or 25% of all Blacks)

To reverse these horrific trends, Blacks must overcome the stigma surrounding homosexual sex, HIV/AIDS and other sexually transmitted diseases to speak honestly with their intimate partners about their risk factors.

Get Tested…

Get Involved…

Find an event in your area recognizing National Black HIV/AIDS Awareness Day. Health fairs and related activities are taking place across the country.

Sources: National Black HIV/AIDS Awareness Day website and CDC website

Learn More: from the CDC about HIV/AIDS Crisis among African Americans, Q&A: Men on the Down Low and What You Can Do

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