Immunohistochemical analysis of ER, PR, Her2 and CK5/6 in infiltrative breast carcinomas in Indian patients.
OBJECTIVE
Breast cancer is biologically a heterogeneous disease. Patients with the same diagnostic profile have markedly different clinical outcomes. Gene expression studies identified distinct breast cancer subtypes that differ in prognosis. Aim is to identify the immunohistochemical subtypes of breast carcinoma and correlate the results with pathological features associated with adverse prognosis in our study population.


METHODS
We included 107 consecutive cases of invasive breast carcinoma and sub classified using immunohistochemical staining for ER, PR, Her2, and CK5/6 into the following subtypes: luminal A, luminal B, basal-like, Her2(+) and unclassified. Associations between tumor subtypes and tumor characteristics were examined.


RESULTS
The proportion of each subtype in our patient population was: luminal A 37.4%, luminal B 11.1%, Her2(+) 29% and basal-like 7.5%. The following variables were significantly associated with IHC breast cancer subtypes: patient age (p<0.05), overall histopathology grade (p<0.001), nuclear grade (p<0.005) and mitotic index (p<0.001). Her2(+) and basal like subtypes were associated with poor differentiation (p<0.01), higher nuclear grade (p<0.05) and high mitotic index (p<0.05).


CONCLUSIONS
Our data show a higher proportion of patients in the study population undergo total mastectomy and harbor poorly differentiated, node positive tumors than reported. There was also a relatively high percentage of the Her2(+) subtype (29%).
Munjal
Kavita
K
Department of Pathology, Sri Aurobindo Institute of Medical Sciences, Indore, Madhya Pradesh, India. kavita_munjal@rediffmail.com
Ambaye
Abiy
A
Evans
Mark F
MF
Mitchell
Jeannette
J
Nandedkar
Shirish
S
Cooper
Kumarasen
K
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D053555:Keratin-5 / Q000378:metabolism*; D053553:Keratin-6 / Q000378:metabolism*; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000378:metabolism*
D014408:Biomarkers, Tumor; D053555:Keratin-5; D053553:Keratin-6; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C503940:KRT5 protein, human; C507569:KRT6A protein, human