Correlation of prognostic clinicopathological parameters via molecular classification in invasive breast carcinomas

Breast cancer is the most common cancer in women worldwide. Determining the prognostic/predictive parameters of breast cancer is important for pathologists and clinicians to understand the clinical course and biological structure of cancer and to decide a personalized treatment approach. The identification of heterogeneity in the tumours led to the urgency of genetic-based molecular classification. Prognostic value of this classification has been a curiosity in last decades. In current study, 232 cases that diagnosed as "Invasive ductal carcinoma, NOS" in Tokat Gaziosmanpaşa University Medical Faculty Hospital dates between 2005-2018 were divided into molecular subtypes by using immunohistochemistry methods. We aimed to determine the prognostic/predictive parameters in itself and the correlation of these subtypes and survival analysis determination. Average age of the cases was 56.13 (± 13.37) and the mean tumour diameter was 29 mm (±17) in the current study. Amount of 182 of the cases (78.4 %) were ER positive, 153 (65.9 %) were PR positive, and 97 (41.8 %) were HER-2 positive. A statistically significant correlation was found between tumour diameter and grade and PNI, grade and ER and PR status, LVI with PNI, LN metastasis and metastatic LN count, ER with PR and HER-2 status, PR and HER-2 status. All the data from analyses were consistent with the literature. Among the parameters that significantly changed the mean survival rate in survival analysis were found as the patient age, tumour size, LVI, PNI, axillary dissection status, LN metastasis status. Amount of 124 patients from our cases (53.4 %) were luminal A, 72 (31.0 %) were luminal B, 25 (10.8 %) were rich in HER-2, 11 (4.7 %) were detected as triple negative subtype. Molecular subtype, tumour diameter, LVI, PNI, LN status, and metastatic LN number were found to be consistent with the literature. A statistically significant relationship was found between the molecular subtypes and grade parameters. In conclusion improving the classification with molecular studies, determining whether molecular subtypes have prognostic/predictive significance by performing in larger series of cases, and their use with routine prognostic parameters will provide benefits in long term patient follow-up. Keywords: invasive breast cancer, molecular classification, molecular subtypes, prognostic factors, predictive factors