The goal of this epidemiologic research study is to find out if various risk factors and certain markers (substances that help identify the presence of cancer) that help predict increased occurrence and prognosis (outcome of disease) of breast cancer differ among Mexican, Mexican-American, and African-American women.

An epidemiologic study looks at the patterns, causes, and control of disease in groups of people. Researchers want to see if various risk factors (such as decreased and delayed fertility, obesity, and a sedentary [low physical activity] lifestyle) and certain markers that cause breast cancer are different in women in the above groups.

If you have breast cancer and you agree to take part in this study, you will be interviewed by a trained interviewer with a questionnaire at a time convenient for you, either during your visit to MD Anderson or The Rose, or by phone. You will be asked questions about your personal demographics (such as your age and race), environmental exposures, medical history, family history of cancer, and other day-to-day lifestyle factors. It should take about 30-40 minutes to complete the interview. Clinical data about your breast cancer treatment will also be collected from your medical records.

You will also have a one-time blood draw (about 3 tablespoons). If blood cannot be drawn or not enough blood can be drawn, you will have a saliva sample taken where you will be required to spit into a container. If you have already donated blood or a saliva sample in the Mexican-American Cohort Study, a portion of that sample may be used instead of having to collect a new sample. Your blood or saliva sample will be used to look at your DNA (genetic material of cells). The study pathologist will look at possible prognostic markers (substances that predict outcome of disease) from tissue obtained from your surgery.

Neither you nor your regular doctor will receive reports of this research study. The results of this research study will not be placed in your health records. All of your information obtained in this study will be kept confidential either in a password-protected computer or in a locked file cabinet in a secure location.

Your participation will be over in this study when all the data has been collected and analyzed.

This is an investigational study. Up to 1,825 women will take part in this multicenter study. Up to 1125 will be enrolled at MD Anderson.

Inclusion Criteria:

1. All women of Mexican and African descent ages 18 years or older.
2. Diagnosis of invasive breast cancer (histologically confirmed invasive adenocarcinoma, including ductal, lobular, medullary, tubular and mucinous cellular patterns) within the past 24 months.
3. Willing to complete a questionnaire.
4. Consent to tissue acquisition (remaining after surgery or preoperative core needle biopsy).

Exclusion Criteria:

1. Male gender
2. Inadequate tissue obtained for the four main clinical markers (ER, PR, Her-2/neu and Ki67).

Woman, 18 years or older, of Mexican descent (Mexican or Mexican-American) or an African-American woman, and have invasive breast cancer during past 12 months.