[en] To determine age-related association of Her-2/neu expression with histological and immunohistochemical prognostic markers in female breast carcinoma. Study Design: Cross sectional, observational study. Place and Duration of Study: Department of Histopathology, Armed Forces Institute of Pathology, Rawalpindi, from January 2004 to December 2007. Methodology: Patients of primary operable female breast carcinoma were categorised as < 40 years (pre-menopausal), 41-50 years (peri-menopausal) and > 50 years (post-menopausal) age groups. Histological type, tumour size, tumour grade and lymph node status were determined while estrogen receptor (ER), progesterone receptor (PR) and Her-2/neu expression were evaluated immunohistochemically. Association of Her-2/neu with histological and immunohistochemical prognostic markers was determined in pre-menopausal, peri-menopausal and post- menopausal age groups using the x2 test for uni- and multivariate analysis. Results: Out of the 722 patients, 230 (31.9%) were in pre-menopuasal, 221 (30.6%) in peri-menopausal and 271 (37.5%) in post-menopausal age group. Infiltrating ductal carcinoma was the pre-dominant subtype in all the age groups. Mean tumour size was 4.3 +- 2.3 cm (range 0.4-17 cm) and lymph node metastasis was seen in 310 (70.8%) cases. Her-2/neu showed association with ER in the all the age groups while PR only showed association in the peri-menopausal and postmenopausal women. Her-2/neu showed no association with tumour size, tumor grade and lymph node metastases in pre-menopausal and peri-menopausal women while it showed positive association with tumour size and lymph node metastasis in the post-menopausal women (p < 0.05). Conclusion: Majority (62%) patients were under 50 years as against the Western epidemiology. Association of Her-2/neu with ER, PR, tumour size and lymph node metastasis was age related as pre-menopausal, peri-menopausal and postmenopausal had variable expression of these prognostic markers with therapeutic and prognostic implications. (author)