Cytogenetic analysis of metaplastic squamous cell carcinoma of the breast inter- and intratumoral heterogeneity

SOX10 - A Novel Marker for the Differential Diagnosis of Breast Metaplastic Squamous Cell Carcinoma

Introduction

Differential diagnosis of metaplastic squamous cell carcinoma of breast (MSCCB) is difficult. In particular, in terms of metastatic MSCCB, because of the low speciality of traditional markers such as mammaglobin, gross cystic disease fluid protein-15 (GCDFP-15) and GATA binding protein 3 (GATA3), the most common problem is differentiating the spread of MSCCB to the lung from a primary lung squamous cell carcinoma. It is urgently required to explore a novel marker to aid in differential diagnosis.

Aim

The aim of this study is to explore a novel marker to aid in the differential diagnosis of MSCCB from other squamous cell carcinomas (SCC) in other organs.

Methods

We tested the expression of SOX10 in 375 human SCC specimens with immunohistochemistry (IHC).

Results

In a series of 20 MSCCB, 9 (45%) were positive for SOX10. All of them were triple-negative MSCCB. Conversely, SOX10 was totally negative in another 205 SCC originating from lung, skin, cervix, oral mucosa, and esophagus. In a series of 150 triple-negative breast cancer and their metastatic foci, SOX10 labeling in the primary tumor and metastasis was 78% and 79.3%, respectively, and the agreement rate was 97.3% (P>0.05).

Conclusion

Our findings demonstrate that SOX10 was recommended for differentiating MSCCB from non-mammary metastasis to the breast, as well as for distinguishing primary SCC from metastatic MSCCB, and SOX10 may be valuable in the pathological diagnosis of breast-derived metaplastic squamous cell carcinoma.

A polymorphism in the lysyl oxidase propeptide domain accelerates carcinogen-induced cancer

The propeptide (LOX-PP) domain of the lysyl oxidase proenzyme was shown to inhibit the transformed phenotype of breast, lung and pancreatic cells in culture and the formation of Her2/neu-driven breast cancer in a xenograft model. A single nucleotide polymorphism (SNP, rs1800449) positioned in a highly conserved region of LOX-PP results in an Arg158Gln substitution (humans). This arginine (Arg)→glutamine (Gln) substitution profoundly impaired the ability of LOX-PP to inhibit the invasive phenotype and xenograft tumor formation. To study the effect of the SNP in vivo, here we established a knock in (KI) mouse line (LOX-PPGln mice) expressing an Arg152Gln substitution corresponding to the human Arg158Gln polymorphism. Breast cancer was induced in wild-type (WT) and LOX-PPGln female mice beginning at 6 weeks of age by treatment with 7,12-dimethylbenz(a)anthracene (DMBA) in combination with progesterone. Time course analysis of tumor development demonstrated earlier tumor onset and shorter overall survival in LOX-PPGln versus WT mice. To further compare the tumor burden in WT and LOX-PPGln mice, inguinal mammary glands from both groups of mice were examined for microscopic lesion formation. LOX-PPGln glands contained more lesions (9.6 versus 6.9 lesions/#4 bilateral). In addition, more DMBA-treated LOX-PPGln mice had increased leukocyte infiltrations in their livers and were moribund compared with DMBA-treated WT mice. Thus, these data indicate that the Arg→Gln substitution in LOX-PP could be an important marker associated with a more aggressive cancer phenotype and that this KI model is ideal for further mechanistic studies regarding the tumor suppressor function of LOX-PP.