Breast carcinomas are the most common of the malignant tumours and the leading cause of cancer-related death in women with more than one lakh cases occurring worldwide annually [1]. It accounts for 25-32 percent of all cancers in women in India and 12.5 percent worldwide[2]. The important morphologic prognostic factors in invasive carcinoma of the breast include the size of the primary tumour, microscopic grade, axillary lymph node metastasis, blood and lymph vessel emboli, tumour necrosis, skin invasion and nipple invasion[3]. Other possible prognostic parameters like cell proliferation index, estrogen receptor, progesterone receptor, Her2 neu receptor status, p53, bcl-2 are of growing interest [4]. Some studies have shown an independent prognostic significance of histologic grade in breast cancer[5-7] although grading is a subjective evaluation that may have problems with reproducibility[8,9].

The grading of breast cancer was first suggested in 1957 by Bloom and Richardson which was based mainly on architectural features. It was modified by Nottingham and the grade is now obtained by adding up the score for the tubule formation, nuclear pleomorphism, mitotic count.10 The Nottingham modification of the Scarff- Bloom- Richardson (NSBR) grading system provides a platform for uniformity in grading[10,12]. The Nottingham Prognostic Index (NPI), is calculated from three parameters namely tumour size, lymph node stage and histologic grade[13]. It predicts prognosis and helps to distinguish groups of patients suitable for different forms of therapy[13].

The mechanism of progression is not completely recognised. Research suggests that the extracellular part of cadherin, via the ions of calcium, influences catenin with similar molecules on the neighbouring cell. Thus, they create an adhesive complex that maintains cells in compact connection [14]. The cancerous process results in the reduction of the amount of cadherin, which in turn results in disorder in the transition of intracellular signals, and loosened intercellular connections. This leads to increased cells’ invasiveness and ability to migrate[15]. Previous data confirm that diminished E-cadherin expression is seen in patients suffering from breast, lung, prostate and stomach cancer[16]. and this correlated with histological grading/reduced variations/of cancer, presence of distant metastasis, and worse prognosis [17].

Table-1: Histological grading using Nottingham modification of Scarff Bloom Richardson system [10].

Table-2: The scores are of the histological grading[10]

Scoring of E-cadherin: The procedure followed for IHC staining is according to standard guidelines. IHC stained sections were observed under light microscopy and the staining was scored. E-cadherin staining interpretation has been adapted from a study done by Esposito N and David J Dabbs, published in Modern Pathology in 200724.

• The immunoreactivity with E-cadherin was scored semiquantitatively as follows:
• Strong inter-membranous staining in >75%= 3+; moderate staining in 26- 75%= 2+, weak staining in 1-25%= 1+, absence of membranous staining= 0 Cases were grouped as ‘preserved,’ when positivity was strong membranous, and occurred in more than 75% of the neoplastic epithelial cells and ‘aberrant’ in all the remaining cases, including the ones where staining was absent[26].

Statistical analysis: It was done using “R” software and the relationship between clinicopathological parameters, IHC grading, and histopathological grading was established using Fischer exact test.

In the present study, age ranged from 32 to 70 years and the mean age ± SD was 49.7± 10.29 years. Majority, 10 cases (33.4%) occurred in 41- 50 years age group followed by 9 (30%) in 51-60 years, 7(23.3%) in 31-40 years, and 4(13.3%) in 61-70 years age group (Table – 3).

The predominant histologic subtype was infiltrating ductal carcinoma (NOS) amounting to 27 cases (90%), followed by 2 cases (6.7%) of intracystic papillary carcinoma and one case (3.3%) of invasive lobular carcinoma.

Table-6: Clinical and Gross features in 27 cases of IDC NOS

Table-7: Microscopic features of 27 cases of IDC-NOS

Of the 27 IDC NOS specimens, 19 were of MRM, 7 were of lumpectomy, and one was of TRM. In the majority of the cases, the cut surface showed a grey-white tumour with infiltrating border and firm to hard in consistency (Table – 6). Histologically, 19 cases (70.4%) are grade 2 tumours, followed by 6 (22.2%) of grade 1, and 2 (7.4%) of grade 3.

immunostaining (Table – 17) IHC scoring: The interpretation of E-cadherin immunostaining was adapted from a study done by Esposito and David Dabbs [24].

Table-9: Interpretation of E-cadherin

In the present study, 14 cases (46.7%) showed +3 E-cadherin grade, i.e, strong intermembranous expression in > 75% of tumor cells, 7 cases (23.3%) showed +2, i.e, moderate staining in 26- 75 % of cells, and 8 cases (26.7%) showed +1, i.e, weak membranous staining in < 25 % of tumor cells. One case (3.3%) was invasive lobular carcinoma which showed a complete absence of membrane staining (Table – 9). Grade of +3 (46.7%) was considered as a preserved expression of E-cadherin while +2, +1 and 0 grades, were considered as aberrant expression of E-cadherin, which accounted for 16 cases (53.3%).

Graph – 1: Correlation between the E-cadherin immunostain grading and the lymph node status

In this study, 1 (3.3%) case showed 0 grade, 8 (26.7%) cases showed + 1, 7 (23.3%) showed + 2 and 14 (46.7%) showed + 3E-cadherin immunostain. The case which showed 0 grade had a positive lymph node. Of the 8 cases (26.7%) of +1, 4 showed lymph node positivity, of the 7 cases of +2 grade, only 1 showed positivity and of 14 cases (46.7%) of +3, 7 showed positive and 7 showed negative lymph nodes. In 5 cases, lymph nodes were not retrieved. The p-value was at 0.046, hence not correlating with the E-cadherin loss (graph 1).

In the present study, most of the tumours ranged between 2-5cm, which correlated with the studies done by Ayadi L et al.[35]. and Muddawa et al.[22].The second commonest size was found to be < 2cm which correlated with Muddawa et al. [22]. The least number of cases showed tumour size of > 5cm which correlated with Ayadi et al. [35].

27 cases (90%) were Infiltrating ductal carcinoma (NOS) was the commonest histological type with 27 cases (90%) correlating with the other studies like that of Zafrani et al. [21].and Satti MB et al. [36]. In the present study, 21 cases (70%) were of histological grade 2, followed by 7 cases (23.3%) of grade 1 and 2 cases (6.7%) of grade 3 of the modified Scarff Bloom Richardson grading system. Similar observations were made by P Querzoliet al.²⁵.

Kowalski et al.²⁶ had 23% of tumours of grade 3 and 20%of tumours of grade. In the current study, 13 cases (43.3%), showed nodal metastasis, 12 (40%) were negative for tumour deposits while in 5 (16.7%) cases, nodes were not available for examination. Kowalski et al.[26]. found majority of lymph node status as positive (72%) while Onitilo AA et al.[37].

In our study, histological grade 3, showed 100% aberrant expression of E-cadherin which is comparable with Sekar et al. [38]. followed by histological grade 1 with 71.4% and grade 2 with

Correlation between E-cadherin expression and histological type: In our study, 48.3% of IDC NOS showed preserved expression of E-cadherin which is comparable with the study of Kowalski et al.[26] that showed 55% preserved expression.

Hence in our study, we found that there was no significant correlation of E-cadherin expression with the histological type (p = 0.19).In our study, we found that there was no significant correlation of the E- Cadherin expression with the size of the tumour (p = 0.4) as 48% of tumours with tumour size ≥ 2 cm showed aberrant expression while it was preserved in 52%. Horne et al.[40] demonstrated that, 55% of tumours with tumour size ≥ 2cm showed aberrant expression vs. 45% with preserved E-cadherin expression. Sekar et al.[39]. observed, that 70% of tumours with size ≥ 2cm showed aberrant expression while only 30% showed preserved expression, which is not comparable to our study.

Our study was an attempt to understand the E-cadherin expression, its ability to distinguish between infiltrating ductal and lobular breast carcinomas, and its correlation with clinicopathological parameters. No correlation has been found with E-cadherin expression and histological type of carcinoma, or histopathological grade, necrosis, calcification, lymphovascular invasion and lymph node status. In contrary to the previous studies[24] which established that aberrant E-cadherin expression skews the diagnosis towards invasive lobular carcinoma rather than invasive ductal carcinoma of the breast, our study revealed 51.7% of IDC cases with aberrant expression poses a question as to how reliable a marker, E-cadherin is, in differentiating ductal and lobular invasive carcinomas in breast, hence it may not have significance in routine use.

Differentiation between infiltrating lobular and ductal carcinomas cannot be made by using E-Cadherin alone. There is a necessity to use newer markers to make this distinction. Recent research has shown the switch of E-cadherin to N-cadherin expression in invasive ductal carcinomas. Further studies on these emerging markers have to be done as there is a potential for newer cancer therapies.

Dr. Shruthi Thota: Data collection, data compiling, literature review, manuscript preparation, manuscript editing, final approval.