EPIDEMIOLOGY Differences in biological features of breast cancer between Caucasian (Italian) and African (Tanzanian) populations D. Amadori • P. Serra • S. Bravaccini • A. Farolfi • M. Puccetti • E. Carretta • L. Medri • O. Nanni • M. M. Tumedei • J. Kahima • N. Masalu Received: 27 December 2013 / Accepted: 27 February 2014 / Published online: 23 March 2014 Ó Springer Science+Business Media New York 2014 Abstract Information on hormone receptor and human epidermal growth factor receptor-2 (HER2) expression in breast cancer is acknowledged as mandatory for prognostic stratification and treatment planning. Data on the biological features of African breast cancers are poor. We decided to compare histopathological and biomolecular characteristics (estrogen and progesterone receptor—ER, PgR, and HER2) of Tanzanian and Italian breast cancers. Differences in pro- liferating index and androgen receptor (AR) expression in triple-negative patients from the two case series were also assessed. Of the 103 consecutive patients seen at the Bug- ando Medical Center (Mwanza, Tanzania) from 2003 to 2010, who underwent biopsy or surgical resection of primary breast cancer, 69 patients had tissue samples that were evaluable for estrogen receptor (ER), progesterone receptor (PgR), and HER2. Histopathological assessment and bio- molecular determinations were performed at the Cancer Institute of Romagna (IRST IRCCS, Meldola, Italy). Cau- casian breast cancers were randomly extracted from an electronic database and matched (1:2 ratio) for year of diagnosis and age at diagnosis. Median age of both popula- tions was 51 years (range 27–84). With respect to Caucasian tumors, Tanzanian breast cancers at diagnosis more fre- quently showed high histological grade (mainly grade 3) (P = 0.03), advanced clinical stage (III or IV) (P \ 0.001), ER negativity (52.2 %, P \ 0.001) and high proliferation (P = 0.0002). Triple-negative tumors were over-repre- sented in Tanzanian women. AR was positive in 38.5 and 38 % of triple-negative Tanzanian and Italian breast cancers, respectively. Our results show that histopathological and biomolecular characteristics in Tanzanian and Italian breast cancers differ substantially. The high frequency of poorly differentiated, ER-negative, highly proliferating tumors, together with advanced stage at presentation, could be con- sidered as the main prognostic factors linked to the high mortality rates for breast cancer in the African population. Keywords Breast cancer Á Biological features Á Tanzanian population Á Caucasian population Introduction The estimated age-standardized rates for breast cancer incidence in sub-Saharan Africa range from 15 to 53 per 100,000 women, which are lower than those in Western countries [1]. However, the cancer burden reported for sub- D. Amadori (&) Á A. Farolfi Department of Medical Oncology, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Via P. Maroncelli 40, 47014 Meldola, Italy e-mail: d.amadori@irst.emr.it P. Serra Á E. Carretta Á O. Nanni Unit of Biostatistics and Clinical Trials, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Italy S. Bravaccini Á M. M. Tumedei Biosciences Laboratory, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Italy M. Puccetti Pathology Unit, S. Maria delle Croci Hospital, Ravenna, Italy L. Medri Pathology Unit, Morgagni-Pierantoni Hospital, Forlı `, Italy J. Kahima Pathology Unit, Bugando Medical Center, Mwanza, Tanzania N. Masalu Oncology Unit, Bugando Medical Center, Mwanza, Tanzania 123 Breast Cancer Res Treat (2014) 145:177–183 DOI 10.1007/s10549-014-2903-0