The prevalence of intrinsic subtypes and prognosis in breast cancer patients of different races.
A recent report indicated that a high prevalence of basal-like breast tumors (estrogen receptor [ER]-negative, progesterone receptor [PR]-negative, human epidermal growth factor receptor [HER] 2-negative, and cytokeratin 5/6-positive and/or HER1-positive) could contribute to a poor prognosis in African American women with breast cancer. It has been reported that Japanese women with breast cancer have a significantly better survival rate than other races in the USA. These findings suggest that breast cancers in Japanese women have favorable biological characteristics. To clarify this hypothesis, we conducted a cohort study to investigate the prevalence of intrinsic subtypes and prognosis for each subtype in 793 Japanese patients. This study revealed a very low prevalence (only 8%) of basal-like breast tumors with aggressive biological characteristics in Japanese patients. Survival analysis showed a significantly poorer prognosis in patients with basal-like tumors than in those with luminal A tumors (ER- and/or PR-positive, and HER2-negative) with favorable biological characteristics. These findings support the hypothesis that breast cancers in Japanese women have more favorable biological characteristics and a better prognosis than those in other races. In conclusion, the prevalence of basal-like breast tumors could influence the prognosis of breast cancer patients of different races. The prevalence of intrinsic subtypes should be taken into account when analyzing survival data in a multi-racial/international clinical study.
Kurebayashi
Junichi
J
Department of Breast and Thyroid Surgery, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-0192, Japan. kure@med.kawasaki-m.ac.jp
Moriya
Takuya
T
Ishida
Takanori
T
Hirakawa
Hisashi
H
Kurosumi
Masafumi
M
Akiyama
Futoshi
F
Kinoshita
Takayuki
T
Takei
Hiroyuki
H
Takahashi
Kaoru
K
Ikeda
Masahiko
M
Nakashima
Kazutaka
K
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D001943:Breast Neoplasms / Q000145:classification / Q000175:diagnosis* / Q000208:ethnology* / Q000401:mortality; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008875:Middle Aged; D015995:Prevalence; D011379:Prognosis; D016019:Survival Analysis