DNA mismatch repair protein expression and microsatellite instability in primary mucosal melanomas of the head and neck

The programmed cell death protein-1/programmed cell death ligand 1 expression, CD3+ T cell infiltration, NY-ESO-1 expression, and microsatellite instability phenotype in primary cutaneous melanoma and mucosal melanoma and their clinical significance and prognostic value: a study of 89 consecutive cases

We evaluated the expression of programmed cell death protein-1 (PD-1), programmed cell death ligand 1 (PD-L1), and NY-ESO-1 antigen; the infiltration of CD3+ T cells; and the microsatellite instability (MSI) phenotype, as well as the relationship of each factor to survival in malignant melanoma patients. Malignant melanoma samples from 89 patients were stained by immunohistochemistry to evaluate PD-1, PD-L1, CD3+ tumor-infiltrating lymphocytes (TILs), NY-ESO-1, and MSI. PD-1 and PD-L1 were expressed in 19.1 and 32.6% of the 89 samples, respectively. There was a significant correlation between PD-1 and PD-L1 expression (r = 0.207, P = 0.046). High infiltration of CD3+ T cells was observed in 41.6% of the samples, and increased cell infiltration was associated with increased PD-1 expression (P = 0.001). NY-ESO-1 antigen was detected in 13.5% of all samples, and the expression of NY-ESO-1 was positively correlated with the expression of PD-1 (P < 0.001). In our research, MSI was detected in 18 samples (20.2%). Survival analysis showed that a high infiltration of CD3+ T cells was related to longer progression-free survival (PFS) [24.0 months, 95% confidence interval (CI): 7.4-40.6 vs. 11.0 months, 95% CI: 7.1-12.9, P = 0.031], similarly, the median overall survival (OS) of the CD3+ T cell high-infiltration patients was also longer (53.0 vs. 38.0 months), but with no statistical significance (P = 0.200). The results for the immune markers mentioned above provide a theoretical basis for the prognosis and immunotherapy selection of malignant melanoma patients.

A study of mucosal melanoma of the oral cavity in India: a rare tumor

Malignant melanomas involving the mucosa are rare and aggressive lesions. Their rarity has made the formulation of staging and treatment protocols very difficult, as most of the available information comes from case reports and small case series. We conducted a retrospective study to analyze the behavior of melanomas of the oral mucosa in patients who were treated at Tata Memorial Hospital in Mumbai, a tertiary care referral center for malignancies and one of the largest cancer centers on the Indian subcontinent. During the 22-year period from January 1986 through December 2007, we found only 13 such cases, which had occurred in 8 men and 5 women, aged 26 to 70 years (mean: 37.5). All patients had been offered surgery with curative intent. Mucosal melanomas have exhibited a greater tendency for distant recurrence than for local treatment failure, which is why adjuvant radiation therapy has not been shown to confer any consistent benefit. In our study, only 3 of the 13 patients (23.1%) remained alive 2 years after diagnosis, despite aggressive treatment. Tumor staging, optimal treatment, and prognostic factors for oral mucosal melanoma are far from clear, and further research is needed. Despite the small number of patients in this study, it still represents one of the largest series of oral mucosal melanoma patients in India.

Reduced expression of mutS homolog 2 and mutL homolog 1 affects overall survival in laryngeal squamous cell carcinoma patients: Investigation into a potential cause

The risk factors affecting the survival rates of laryngeal carcinoma are not well understood. In this study, we investigated the expression status of mutS homolog 2 (MSH2) and mutL homolog 1 (MLH1) and examined the relationship between these two molecules and overall survival rates in laryngeal cancer. We also explored the potential reason for the altered expression of these two genes. Using real-time polymerase chain reaction and western blotting, we detected MSH2 and MLH1 expression in laryngeal cancer tissue samples. We collected a retrospective cohort with 180 laryngeal cancer patients, and inspected MSH2 and MLH1 staining with tissue microarray immunohistochemistry. Prognostic value of clinicopathological characteristics was evaluated by statistical analysis. Laryngeal carcinoma cells were co-cultured with Helicobacter pylori (H. pylori) bacteria. MSH2 and MLH1 were expressed at lower levels compared to those of adjacent tissues in 21 laryngeal carcinoma patients. Patients with negative expression of MSH2 and MLH1 tended to have a higher risk of mortality compared to patients with positive expression (HR=4.38; HR=3.0, respectively). Cigarette smoking rate was higher in the MLH1 expression positive group. H. pylori infection reduced the MSH2 and MLH1 expression levels of laryngeal carcinoma cell lines within co-culture conditions. It is suggested that the altered expression levels of MSH2 and MLH1 probably affect the overall survival of laryngeal carcinoma patients. H. pylori infection may have an effect on the expression of MSH2 and MLH1 in laryngeal carcinoma patients.

Spindle cell amelanotic lesion of the tongue: a diagnostic and therapeutic challenge

Melanomas occurring in the tongue are rarer, and when nonpigmented they are often misdiagnosed as squamous cell carcinoma. We report a 50-year-old woman who presented with a 3 × 2 cm soft swelling of mucosal color on the right lateral border of the tongue. The patient had multiple recurrences and was treated by radical radiotherapy, was operated thrice and received adjuvant 5 MIU interferon weekly. During the last surgery, she developed multiple cerebral infarcts and died on the fifth postoperative day. Oral amelanotic melanoma is a very aggressive and potential lethal tumor that often presents as diagnostic dilemma.

Evidence that dysregulated DNA mismatch repair characterizes human nonmelanoma skin cancer

BACKGROUND

In addition to an established role in the repair of postreplicative DNA errors, DNA mismatch repair (MMR) proteins also contribute to cellular responses to exogenous DNA damage. Previously, we have shown that Msh2-null mice display increased sensitivity to ultraviolet (UV) B-induced tumorigenesis, but squamous cell carcinomas (SCC) generated are microsatellite stable, suggesting a role for MMR other than postreplicative repair in UV-induced cutaneous tumour formation.

OBJECTIVES

We questioned whether there was evidence of MMR dysfunction in human SCC, thus validating the mouse models of MMR-dependent UVB-induced skin cancer.

METHODS

Using tissue microarrays we examined both nuclear and cytoplasmic levels of MMR proteins MSH2, MSH6, MSH3, MLH1 and PMS2 in more than 200 cases of cutaneous SCC and basal cell carcinoma (BCC).

RESULTS

We found that subsets of these 10 MMR protein measures were increased in nonmelanoma skin cancer (NMSC) compared with normal epidermal samples; this was particularly true of SCC. In fact, based on post hoc tests and MMR protein distribution patterns, BCC was distinct from SCC. With the exception of nuclear MSH2, the BCC had lower levels of identified MMR protein measures than SCC. We believe this to be important because not only is SCC more aggressive than BCC, but evidence suggests that these two NMSC subtypes arise through different molecular pathways.

CONCLUSIONS

In combination with previously established roles for MMR proteins in response to UVB-induced DNA damage, our data point towards an expanded perspective of the importance of MMR proteins in the suppression of UVB-induced tumorigenesis and, potentially, tumour behaviour.