INK4-ARF and p53 mutations in metastatic cutaneous squamous cell carcinoma: case report and archival study on the use of Ink4a-ARF and p53 mutation analysis in identification of the corresponding primary tumor

Molecular Mechanisms of Cutaneous Squamous Cell Carcinoma

Non-melanoma skin cancers are cutaneous malignancies representing the most common form of cancer in the United States. They are comprised predominantly of basal cell carcinomas and squamous cell carcinomas (cSCC). The incidence of cSCC is increasing, resulting in substantial morbidity and ever higher treatment costs; currently in excess of one billion dollars, per annum. Here, we review research defining the molecular basis and development of cSCC that aims to provide new insights into pathogenesis and drive the development of novel, cost and morbidity saving therapies.

Concurrent Endometrial Intraepithelial Carcinoma (EIC) and Serous Ovarian Cancer: Can EIC Be Seen as the Precursor Lesion?

Objective

The pathogenesis of serous ovarian carcinoma (SOC) is still unknown. Recently, endometrial intraepithelial carcinoma (EIC) was proposed to be the precursor lesion of SOC. This study examines the model of EIC as precursor for SOC.

Methods

Cases of SOC with a noninvasive or superficially invasive serous lesion, a hyperplastic lesion with/without atypia, or EIC in the endometrium were selected for inclusion in this study. Tissue sections from both ovaries, the fallopian tubes, and the uterus were extensively reviewed by an expert gynecopathologist. For both EIC and SOC, immunostaining for p53, Ki-67, estrogen receptor, and progesterone receptor; TP53 mutation analysis; and in situ ploidy analysis were performed.

Results

Nine cases of SOC with concurrent EIC in the endometrium were identified. Immunostaining for p53, Ki-67, estrogen receptor, and progesterone receptor revealed almost identical expression patterns and similar intensities in each pair of EIC and coincident SOC. Identical TP53 mutations were found in SOC and coinciding EIC in 33% of the cases, suggesting a clonal origin. DNA ploidy analysis, as a marker for neoplastic progression, demonstrated an increased number of aneuploid nuclei in SOC compared to their corresponding EIC (P = 0.039). In addition, the mean amount of DNA per nucleus in SOC was higher (ie, more aneuploid) compared to EIC (P = 0.039).

Conclusion

This study provides a first indication of EIC as possible precursor lesion for SOC. This finding could have major clinical implications for future ovarian cancer management and underscores EIC as a possible target for early SOC detection and prevention.

CDKN2A but not TP53 mutations nor HPV presence predict poor outcome in metastatic squamous cell carcinoma of the skin

Genetic alterations in metastatic cutaneous squamous cell carcinoma (CSCC) which might serve as prognostic biomarkers are not well investigated. We investigated the mutation status and protein expression of the CDKN2A (INK4a-ARF) and TP53 genes in metastatic CSCCs and correlated this with clinicopathological variables, HPV presence, and survival data. Sequence analysis was performed on formalin-fixed and paraffin-embedded tissue of 35 metastases and their primary tumors, and was correlated with immunohistochemical stainings for p53, p16 and p14. Beta-PV and alpha-PV DNA was detected using PCR-based assays. Kaplan-Meier and Cox regression methods were used for survival assessment. CDKN2A was mutated in 31% of the metastases and their primary tumors, while the TP53 gene was mutated in 51% of the metastases. P53 protein expression was significantly associated with missense type of mutations (p = 0.002). No persistent HPV types were detected. CDKN2A mutations were significantly associated with disease-specific death (p = 0.001). A significant difference was observed in disease-specific survival between patients with or without a CDKN2A mutation (p = 0.010), while this was not the case for TP53. At univariate Cox's regression analysis tumor size (p = 0.010), invasion depth (p = 0.030) and CDKN2A mutations (p = 0.040) were significantly related to shorter disease-specific survival. At multivariate Cox's regression only tumor size had an adverse effect on survival (p = 0.002). In conclusion, our study indicates that the CDKN2A mutation status might be of prognostic value in metastatic CSCCs. In most cases, CDKN2A and TP53 mutations are early genetic events in CSCC tumorigenesis. The possible role of HPV in metastatic CSCC needs further exploration.

Molecular biology of basal and squamous cell carcinomas

Basal cell carcinomas and Squamous cell carcinomas are the two most common human cancers. The incidence of these two types of cancer is estimated to double within 20 years. Identification of the key molecular events is critical in helping us design novel strategies to treat and to prevent these cancers. For example, identification of hedgehog signaling activation has opened up many opportunities for targeted therapy and prevention of basal cell carcinomas. Significant progress has also been made in our understanding of squamous cell carcinomas of the skin. In this chapter, we will focus on major recent developments in our understanding of basal cell carcinomas and squamous cell carcinomas at the molecular levels and their clinical implications.

CDKN2A (INK4A-ARF) Mutation Analysis to Distinguish Cutaneous Melanoma Metastasis From a Second Primary Melanoma

The histologic differential diagnosis between a second primary cutaneous melanoma and cutaneous melanoma metastasis in a patient with a previous history of melanoma can be very difficult. This case report describes the first application of CDKN2A mutation analysis for discriminating a cutaneous melanoma metastasis from a new primary melanoma. In 2005, we received a skin excision of the right arm of a 38-year-old female patient for second opinion. Histologically, we considered the lesion to be a melanoma. The patient had a history of superficial spreading melanoma in the right subclavicular region, with a Breslow thickness of 1.1 mm, in 1998. The morphology showed resemblance to the present melanoma on the right arm, but the differential diagnosis between metastasis or second primary melanoma could not be made with certainty based on histology alone. We decided to perform TP53 and CDKN2A mutation analysis on both tumors. Molecular analysis revealed that both the melanoma of 1998 and of 2005 contained an identical CDKN2A mutation (a deletion in exon 1alpha, c.95_112del (p.Leu32_Leu37del)), which was absent in normal control tissue of the patient, thereby excluding a germline mutation. TP53 mutations were absent in both tumors and in normal skin. Based on these molecular findings the present melanoma on the right arm was diagnosed as a metastasis. Seven months later the patient died of widespread metastatic disease confirming the metastatic nature of the lesion. This case illustrates that molecular analysis can contribute to the sometimes-difficult differentiation between a second primary melanoma and a melanoma metastasis.