Expression of c-erbB3 protein was investigated in 104 primary breast carcinomas comprising nine comedo ductal carcinoma in situ (DCIS), 91 invasive ductal carcinomas and four invasive lobular carcinomas using two monoclonal antibodies, RTJ1 and RTJ2. Of the 91 invasive ductal carcinomas, seven contained the comedo DCIS component adjacent to the invasive component. An immunohistochemical technique was used to evaluate the association between expression of c-erbB3 and clinical parameters and tumour markers such as epidermal growth factor receptor (EGFR), c-erbB2, cathepsin-D and p53 in archival formalin-fixed paraffin-embedded tumour tissues. Our results indicated that RTJ1 and RTJ2 gave identical staining patterns and concordant results. It was found that the overexpression of c-erbB3 protein was observed in 67% (6/9) of comedo DCIS, 52% (44/84) of invasive ductal carcinomas, 71% (5/7) of carcinomas containing both the in situ and invasive lesions and 25% (1/4) of invasive lobular carcinomas. A significant relationship (P < 0.05) was observed between strong immunoreactivity of c-erbB3 protein and histological grade, EGFR and cathepsin-D, but not with expression of c-erbB2, p53, oestrogen receptor status, lymph node metastases or age of patient. However, we noted that a high percentage of oestrogen receptor-negative tumours (59%), lymph node-positive tumours (63%) and c-erbB2 (63%) were strongly positive for c-erbB3 protein. We have also documented that a high percentage of EGFR (67%), c-erbB2 (67%), p53 (75%) and cathepsin-D-positive DCIS (60%) were strongly positive for c-erbB3. These observations suggest that overexpression of c-erbB3 protein could play an important role in tumour progression from non-invasive to invasive and, also, that it may have the potential to be used as a marker for poor prognosis of breast cancer.
Overexpression and amplification of cyclin D1 were investigated by immunohistochemistry and differential polymerase chain reaction (dPCR) in 440 formalin-fixed primary breast carcinoma tissues. Overexpression of cyclin D1 was detected in 60% (263/440) and amplification of cyclin D1 was noted in 27% (119/440) of the primary breast carcinomas. Molecular analysis demonstrated that cyclin D1 was amplified in 30% (7/23) of the comedo DCIS, 22% (9/41) of the comedo DCIS and 32% (13/41) of the adjacent invasive ductal carcinomas, 30% (82/270) of the invasive ductal carcinomas, 27% (9/33) of the invasive lobular carcinomas, 19% (4/21) of the colloid carcinomas and 13% (2/15) of the medullary carcinomas. Cyclin D1 was amplified in 11% (2/19) of the invasive ductal carcinomas but not in the adjacent non-comedo DCIS lesions. Our observation showed that cyclin D1 was strongly positive in 61% (14/23) of the comedo subtype, 61% (11/18) of the non-comedo subtype, 59% (24/41) of the comedo DCIS and 63% (26/41) of the adjacent invasive ductal carcinomas, 53% (10/19) of the non-comedo DCIS and 58% (11/19) of the adjacent invasive lesions, 58% (157/270) of the invasive ductal carcinomas, 73% (24/33) of the invasive lobular carcinomas, 52% (11/21) of the colloid carcinomas and 27% (4/15) of the medullary carcinomas. A significant association was observed between in situ components and adjacent invasive lesions for cyclin D1 expression (p<0.05) and amplification (p<0.05). A significant relationship was noted between amplification of cyclin D1 and lymph node metastases (p<0.05) but not with histological grade (p>0.05), estrogen receptor status (p>0.05) and proliferation index (Ki-67 and PCNA) (p>0.05). However, overexpression of cyclin D1 was statistically associated with well differentiated tumors (p<0.05) and estrogen receptor positivity (p<0.05). No relationship was seen with nodal status (p>0.05) and proliferation index (Ki-67 and PCNA) (p>0.05). These observations suggest that tumors positive for cyclin D1 protein may have features of good prognosis but amplification of cyclin D1 gene could be an indicator of tumors with poor prognostic features. Although majority of the Malaysian patients belong to younger age group (<50 years old), amplification and expression of cyclin D1 was not statistically associated with patient age (p>0.05). These observations indicate that amplification and up-regulation of cyclin D1 may be independent of patient age. Moreover, overexpression and amplification of cyclin D1 in preinvasive, preinvasive and adjacent invasive lesions, and invasive carcinomas suggest that the gene may play an important role in early and late stages of breast carcinogenesis.
Amplification of int-2/FGF-3 gene was investigated by differential polymerase chain reaction (dPCR) in 440 archival primary breast carcinoma tissues. Of these, 23 were comedo ductal carcinoma in situ (DCIS), 18 were non-comedo DCIS, 41 were comedo DCIS with adjacent invasive ductal carcinomas, 19 were non-comedo DCIS with adjacent invasive ductal carcinomas, 270 were invasive ductal carcinomas, 33 were invasive lobular carcinomas, 21 were colloid carcinomas and 15 were medullary carcinomas. Int-2 was amplified in 22% (96/440) of the primary breast carcinomas. It was shown that int-2 was amplified in 13% (3/23) of the comedo DCIS, 17% (7/41) of the comedo DCIS and 29% (12/41) of the adjacent invasive ductal carcinomas, 26% (71/270) of the invasive ductal carcinomas, 18% (6/33) of the invasive lobular carcinomas, 10% (2/21) of the colloid carcinomas and 13% (2/15) of the medullary carcinomas. In contrast, int-2 was not amplified in non-comedo DCIS and invasive ductal carcinomas with adjacent non-comedo DCIS lesions. A significant association was observed between int-2 amplification in the in situ components and adjacent invasive lesion (P<0.05). All tumors with int-2 amplification in the in situ lesions (7/7) also demonstrated same degree of amplification in the adjacent invasive components. However, 9% (5/53) of the tumors with no amplified int-2 gene in the in situ components showed int-2 amplification in the adjacent invasive lesions. A significant relationship was noted between amplification of int-2 and lymph node metastases (P<0.05) and poorly differentiated tumors (P<0.05) but not with estrogen receptor status (P>0.05) and proliferation index (Ki-67 and PCNA) (P>0.05). In Malaysia, majority of the patients belong to younger age group (<50 years old) but a comparison of the age groups showed that the amplification of int-2 was not statistically associated with patient age (P>0.05). These observations indicate that amplification of int-2 tends to strengthen the view that int-2 may have the potential to be an indicator of poor prognosis regardless of the age of the patient. Moreover, the presence of int-2 amplification in preinvasive, preinvasive and adjacent invasive lesions, and invasive carcinomas suggest that int-2 could be a marker of genetic instability occurring in early and late stages of tumor development.