Immunohistochemical analysis of laminin 5-γ2 chain expression for differentiation of basal cell carcinoma from trichoblastoma

Expression of laminin332 γ2 at the invasive front is associated with tumor budding and poor prognosis in cutaneous squamous cell carcinoma

Laminin332 is a glycoprotein consisting of α3/β3/γ2 chains, of which the γ2 chain (Ln-γ2) is expressed in tumor cells at the invasive front in many types of malignant tumors. We have previously reported that Ln-γ2 is associated with tumor invasion of cutaneous squamous cell carcinoma (cSCC) in vivo and in vitro. Recently, tumor budding (TB; invasion patterns in small clusters of less than five cancer cells in the stroma at the invasive front) has been reported to be a risk factor for lymph node metastasis in cSCC. Based on these findings, we speculated that expression of Ln-γ2 is related to TB in cSCC and would be an invasive factor that causes lymph node metastasis. In this study, we investigated the relationship between Ln-γ2 expression and clinicopathological findings, including TB, in 102 cases of cSCC using immunohistochemistry. The results showed that high expression of Ln-γ2 at the invasive front correlated with a high TB score. In addition, high Ln-γ2 expression at the invasive front was also associated with lymphatic invasion, lymph node metastasis, and poor prognosis (death or recurrence), as in TB. Furthermore, we showed a positive association between Ln-γ2 expression at the invasive front and Yes-associated protein (YAP) expression in the Hippo pathway. Our results suggest that Ln-γ2 expression at the invasive front may have a role in TB formation via YAP and contribute to prognosis by causing lymphatic invasion and lymph node metastasis. The expression of Ln-γ2 would be useful for risk assessment of lymph node metastasis and poor prognosis in routine practice of cSCC.

Laminin γ2-mediating T cell exclusion attenuates response to anti-PD-1 therapy

PD-1/PD-L1 blockade therapies provide notable clinical benefits for patients with advanced cancers, but the factors influencing the effectiveness of the treatment remain incompletely cataloged. Here, the up-regulation of laminin γ2 (Ln-γ2) predicted the attenuated efficacy of anti-PD-1 drugs and was associated with unfavorable outcomes in patients with lung cancer or esophageal cancer. Furthermore, Ln-γ2 was transcriptionally activated by transforming growth factor-β1 (TGF-β1) secreted from cancer-associated fibroblasts via JNK/AP1 signaling, which blocked T cell infiltration into the tumor nests by altering the expression of T cell receptors. Coadministration of the TGF-β receptor inhibitor galunisertib and chemotherapy drugs provoked vigorous antitumor activity of anti-PD-1 therapy in mouse tumor models. Therefore, Ln-γ2 may represent a useful biomarker to optimize clinical decisions and predict the response of cancer patients to treatment with anti-PD-1 drugs.

Expression of laminin-5 gamma 2 chain predicts invasion of extramammary Paget's disease cell

Extramammary Paget's disease (EMPD) is a rare malignant skin neoplasm characterized by intraepidermal proliferation of tumor cells. The tumor cells of EMPD may sometimes invade into the dermis or metastasize into the regional lymph nodes. Several studies have proposed mechanisms underlying the increased invasiveness of EMPD; however, molecular markers indicating invasiveness have yet to be well characterized. Laminin-5 (Lam-5), a heterotrimer composed of three chains (α3, β3, and γ2), is a major component of the basement membrane in many tissues. One of the chains, Lam-5 γ2, is a marker of invasion, because it often develops as a monomer in malignant neoplasms. We investigated the expression of Lam-5 γ2 and its role for the invasiveness in EMPD. Paraffin-embedded specimens of EMPD obtained from 36 patients were examined immunohistochemically for Lam-5 γ2. The cases adopted into this study comprised 16 cases of intraepidermal lesions and 20 cases with dermal invasion. The basement membrane seen in normal skin disappeared in one-third of non-invasive cases and in most invasive cases. The disappearance of Lam-5 γ2 in the basement membrane and its cytoplasmic expression was more observed in the invasive cases than non-invasive cases. Expression of Lam-5 γ2 may be a biological marker to predict invasiveness of EMPD.

Laminin 332 in cancer: When the extracellular matrix turns signals from cell anchorage to cell movement

Laminin 332 is crucial in the biology of epithelia. This large extracellular matrix protein consists of the heterotrimeric assembly of three subunits - α3, β3, and γ2 - and its multifunctionality relies on a number of extracellular proteolytic processing events. Laminin 332 is central to normal epithelium homeostasis by sustaining cell adhesion, polarity, proliferation, and differentiation. It also supports a major function in epithelial tissue formation, repair, and regeneration by buttressing cell migration and survival and basement membrane assembly. Interest in this protein increased after the discovery that its expression is perturbed in tumor cells, cancer-associated fibroblasts, and the tumor microenvironment. This review summarizes current knowledge regarding the established involvement of the laminin 332 γ2 chain in tumor invasiveness and discusses the role of its α3 and β3 subunits.

Ln-γ 2 chain of laminin-332 is a useful marker in differentiating between benign and malignant sclerosing adnexal neoplasms

AIMS

Laminin (Ln)-γ 2, one of the chains of Ln-332, is a marker of invasive tumours and is frequently expressed as a monomer in malignant tumours. Desmoplastic trichoepithelioma (DTE), some types of basal cell carcinoma (BCC) (infiltrating and morphoeic BCC) and microcystic adnexal carcinoma (MAC) belong to a group of tumours known as sclerosing adnexal neoplasms (SAN) that are frequently difficult to differentiate and often require immunohistochemistry for diagnosis. The aim of this study was to assess the usefulness of Ln-γ 2 expression in the differential diagnosis of DTE, infiltrating/morphoeic BCC, MAC and syringoma.

METHODS AND RESULTS

In this study, we compared the expression of Ln-γ 2 in infiltrating/morphoeic BCC (n = 28), DTE (n = 26), MAC (n = 10) and syringoma (n = 20). Immunohistochemically, Ln-γ 2 positivity was noted in 96% (27 cases) of infiltrating/morphoeic BCC and 90% (nine cases) of MAC, while all DTE and syringoma cases were negative. Furthermore, Ln-γ 2 expression pattern in infiltrating/morphoeic BCC was different from that in MAC. Ln-γ 2 expression was found in the cytoplasm of tumour cells in infiltrating/morphoeic BCC tumour cells, while in MAC linear expression was noted both along tumour nests and in the cytoplasm.

CONCLUSION

Ln-γ 2 is a helpful adjunct in the differential diagnosis of SAN.

A Rare Presentation of Basal Cell Carcinoma Arising within Trichoepithelioma: A Diagnostic Challenge

Differentiating between trichoepithelioma and basal cell carcinoma (BCC) is sometimes diagnostically challenging. We present a case of a 61-year-old male with a BCC arising within a trichoepithelioma, which is rarely reported in the literature. Clinical and histological diagnosis of trichoepithelioma is sometimes complicated by its many similarities to BCC. Therefore, immunohistochemical analysis and adequate tissue sampling are essential in suspicious lesions. In addition, as represented by our patient’s presentation, it is important for clinicians to remember that the presence of a concurrent malignant neoplasm may be masked by the benign nature of a trichoepithelioma and that a superficial shave biopsy may not be sufficient for accurately diagnosing such suspicious lesions.

Vulvar trichoblastoma: case report and literature review

OBJECTIVE

Trichoblastomas are rare and benign tumors that arise from rudimentary hair follicles. Presentation varies from superficial plaques to papular or nodular lesions. Trichoblastomas usually arise on the head or neck. A few cases of other vulvar trichoblastic tumors such as trichofibromas and trichoepitheliomas have been reported to this day, but no such report of vulvar trichoblastoma exists.

MATERIALS AND METHODS

We report the case of a 61-year-old woman who presented with a vulvar trichoblastoma. The woman presented with a lump of the labium majus. She was managed surgically, first by wide excision of the mass followed by a second surgery consisting of a partial vulvectomy. Because surgical margins were positive and there is a potential for malignant transformation, a third surgery was performed. The margins came back negative. A literature review on trichoblastomas was performed, including its potential for malignant transformation, management, and immunohistochemistry to differentiate it from basal cell carcinoma.

RESULTS

Trichoblastomas are benign tumors that have a potential for malignant transformation. These tumors can present aggressive characteristics. Differential diagnosis from basal cell carcinoma can be difficult but is facilitated using immunohistochemistry.

CONCLUSIONS

This is the first case of vulvar trichoblastoma reported in the literature. Although it is a benign tumor, excision with negative margins is recommended because it can be difficult to distinguish from basal cell carcinoma and it has a potential for malignant transformation.

Expression of laminin 5-γ2 chain in cutaneous squamous cell carcinoma and its role in tumour invasion

Background:

Laminin-5 (Ln5), a heterotrimer composed of three chains (α3, β3, and γ2), is a major component of the basement membrane in most adult tissues. One of the chains, Ln5-γ2, is a marker of invasive tumours because it is frequently expressed as a monomer in malignant tumours. Recent studies from our laboratories detected higher levels of Ln5-γ2 expression in basal cell carcinoma (BCC) than in trichoblastoma. Furthermore, Ln5-γ2 overexpression tended to correlate with aggressiveness in BCC.

Methods:

In this study, we compared the expression of Ln5-γ2 in invasive squamous cell carcinoma (SCC, n=62) of the skin to that in preinvasive Bowen’s disease (BD, n=51), followed by analysis of the role of Ln5-γ2 in cancer invasion in vitro.

Results:

Immunohistochemically, the proportion of SCC cases (86%) strongly positive for Ln5-γ2 expression was higher than that of BD (16%). Real-time RT–PCR showed Ln5-γ2 overexpression in SCC cell line, A431, compared with normal keratinocyte cell line, HaCaT. Ln5-γ2 monomer and proteolytically cleaved, biologically active fragments of Ln5-γ2 were identified in SCC tumour extracts. In in vitro raft cultures, which simulate in vivo conditions, Ln5-γ2 siRNA significantly suppressed epidermal growth factor (EGF)-stimulated A431 cell invasion.

Conclusion:

Our results indicate that Ln5-γ2 has a role in cutaneous SCC invasion.