Introduction

The HER-2/neu(c-erbB-2) is an oncogene that encodes a transmembrane glycoprotein with tyrosin kinase activity known as p185, which belongs to the family of epidermal growth factor receptor [₁₂]. Cells transfected with HER-2/neu acquire a more malignant phenotype¸ with stimulation of cell proliferation¸ invasion and metastasis. This has been confirmed in the clinic: women with Her-2/neu positive breast cancer have a worse prognosis than those with Her-2/neu negative cancer [₁₃₄]. although Her-2/neu overexpression has been correlated with poor prognostic tumor characteristics such as higher histological grade¸ S phase fraction¸ increased tumor size¸ increased number of involved lymph nodes¸ absence of lobular histology and negative or lower Estrogen receptor (ER) expression [₁₅] but its role as an independent prognostic factor is not significant in multivariate analysis [₁₆].

Semiquantitative measurement using immunohistochemistery (IHC) for the Her-2/neu membrane receptor protein can accurately predict gene amplification [₇].

Estrogen receptor (ER) correlates inversely with the presence of epidermal growth factor receptor [₁] also it has been suggested that there is an inverse relation between the expression of the progesterone receptor (PR) and Her-2/neu in women with ER⁺ breast cancer [₅₈].

The aim of this study was to determine the relation between Her-2/neu overexpression and other clinicopathological factors in women with operable breast cancer.

Materials and methods

The association between breast tumor characteristics and expression of ER, PR¸ Her-2/neu overexpression, patient’s age, largest tumor size, tumor type and tumor grade were retrospectively evaluated in 226 women with primary breast cancer referred to Armin pathobiology laboratory in 1384. The evaluation of histopathologic characteristics was carried out on paraffin –embedded tissue blocks which were stained with Hematoxylin & Eosin. The Immunohistochemistry staining for ER, PR and Her-2/neu were done on paraffin-embedded tissue blocks according to the envision method using primary monoclonal antibodies ( Dako Kits).

The DAKO scoring system for Her-2/neu was defined as negative for scores 0 &1+ and positive for score 2+ & 3+ and overexpression for score 3+ (Table1)[₁].

Using the H score for ER and PR¸ a negative result was defined as a score of ≤50¸ weakly positive as 51-100¸ moderately positive as 101-200 and strongly positive as >200. Tumor grading was performed according to Richardson & Bloom grading system [₁].

In a univariate analysis the association between ER, PR and Her-2/neu was evaluated and the chi square test was used to examine the categorical variables and the association between ER, PR expression and other clinicopathologic variables.

The results were considered statistically significant if the P value was < 0.05. All analysis were performed with SPSS version 11.0 for windows.

Results

Table 2 summarizes the clinicopathological features of all 226 women with primary operable breast cancer. HER-2/neu was expressed as defined by a DAKO score 3+ and a DAKO score 2+ or 3+ in 21.7% and 36.3% of all patients, respectively.

Table 3 shows data of HER-2/neu overexpression scoring in primary operable breast cancers based on DAKO scoring system.(univariate analysis). There was no correlation between HER-2/neu overexpression and ER state, PR state, tumor grade, tumor size and patient age.

Table 4 shows the frequency of HER-2/neu overexpression in the different ER/PR phenotypes (ER^-PR^-, ER^-PR⁺, ER⁺PR^- and ER⁺PR⁺) of breast cancer. The frequency of HER-2/neu overexpression decreased from ER^-PR^- to ER⁺PR⁺ (30.7% to 18.8%) but this difference was not significant (p=0.057).

Table 5 shows the frequency of HER-2/neu overexpression in the different joint ER/PR phenotypes (ER^-PR^-, ER^-PR⁺, ER⁺PR^- and ER⁺PR⁺) in low and high grade tumors.

The frequency of HER-2/neu overexpression decreased significantly (P<0.05) from ER^-PR^- to ER⁺PR⁺(45.5% to 20.5%) in patients with low grade tumor, also the frequency of HER-2/neu overexpression decreased from ER^-PR^- to ER⁺PR⁺(18.8% to 15.4%) in patients with high grade tumor but this difference was not significant.

Figure 1

Table 1: scoring system for Her-2/neu

Figure 2

Table 2: summarises the clinicopathological features of all 226 women with primary operable breast cancer

Figure 3

Table 3: Association between Her-2/neu overexpression and tumor characteristics in 226 women with primary breast cancer

Figure 4

Table 4: Frequency of HER-2/neu overexpression by joint ER/PR status

Figure 5

Table 5: Frequency of HER-2/neu overexpression for low grade and high grade tumor by joint ER/PR status

Discussion

In our study, we found that 36.3% of cases were HER-2/neu positive (score 2-3) and 21.7% of cases showed HER-2/neu overexpression (score 3). HER-2/neu overexpression is found in 20% to 30% of cases with invasive carcinoma [_19101112].

Presence of estrogen receptor was significantly associated with high nuclear and low histologic grades and older patients' age groups [₁].

We found that 62.4% and 61.5% of cases were ER positive and PR positive, respectively. The percentage of ER positive cases reported in literatures is 60% to 70% [₁₂₁₃] or 70% to 90% [₁₄] and PR positive cases are reported 60% to 70% [₁₄].

Our results show 86.6% of breast cancers were low grade (grade 1-2) and 19.4% were high grade (grade 3). (Missing cases, not included).

In our study 80.8% of cases were Ductal carcioma, 9.5% Lobular carcinoma and 3.6% were other histologic types including Medullary, Colloid, tubular, mucinous carcinoma and adenocarcinoma. (Missing cases, not included).

We compared HER-2/neu overexpression in hormone receptor positives and hormone receptor negatives in relation to other clinicopathologic characteristics in primary operable breast cancer. HER-2/neu overexpression in ER negative cases (28.4%) was higher than ER positive cases (18.4%) and HER-2/neu overexpression in PR negative cases (28.4%) was higher than PR positive cases (18.0%), although these differences were not significant. According to most of the studies, presence of estrogen receptor (ER) and progestron receptor (PR) correlates inversely with HER-2/neu overexpression [_{1911141516171819}].

Patients 50 years of age or younger were more likely to have HER-2/neu overexpression than patients older than 50 years (25.4% versus 15.5%). It should be pointed out that higher rates of HER-2/neu overexpression in young patients have been documented in previous studies [_8910172021], but in other studies, no correlation were found between age of patient and HER-2/neu overexpression [_11162223].

We did not find any correlation between size of the tumor with HER-2/neu overexpression, which is similar to some previous studies [₁₆₂₂₂₄] and disagree with other studies [₉₁₅₁₈].

We also found no correlation between grade of the tumor and HER-2/neu overexpression, which is similar to some studies [_20222325] and disagree with other studies [_111215161819].

The frequency of HER-2/neu overexpression decreased from ER^-PR^- to ER⁺PR⁺ (30.7% to 18.8%) but this difference was not significant (p=0.057). In another study, this decrease was significant [₁₅].

The frequency of HER-2/neu overexpression decreased significantly (P<0.05) from ER^-PR^- to ER⁺PR⁺(45.5% to 20.5%) in patients with low grade tumor, also the frequency of HER-2/neu overexpression decreased from ER^-PR^- to ER⁺PR⁺ (18.8% to 15.4%) in patients with high grade tumor but this difference was not significant (P=0.790). In two other studies, these decreases in low and high grade tumors were significant [₁₄₁₅].

Our results show higher proportion of ER^- and ^{PR- tumors associated with HER-/neu overexpression, also younger patients have higher rate of HER-2/neu overexpression.}