This study reviews the current understanding of the pattern of breast cancer among whites, African Americans, and West Africans who have never immigrated to the US to find better ways of improving the prevention, early detection, and care of breast cancer world-wide. In the United States, the behavior pattern of breast cancer in African-American women differs from that of white women. Among the three populations, breast cancer appears to be least common in nonimmigrant West-African women. The peak incidence in African Americans and West Africans occurs around the premenopausal period while it occurs postmenopausal period in whites. Also, unlike white women, West-African and African-American women present late for treatment with a greater cancer burden and consequently lower survival rates. The predominant histological type is infiltrating ductal carcinoma in the three groups but the highest percentage (33%) of infiltrating poorly differentiated anaplastic carcinoma occurs in West Africans. Menstrual and obstetric history, obesity, and high body mass index status appear to be greater specific risk factors among African Americans than among West Africans. African Americans and West Africans have three "Ls" in common: late stage in seeking treatment, lower age at peak incidence with severe tumor burden, and consequently lower survival rates. There is a need for more detailed population-based research at molecular levels to elucidate the basis for some of these features.