PD-L1, LAG3, and HLA-DR are increasingly expressed during smoldering myeloma progression.

Symptomatic multiple myeloma (MM) is a plasma cell neoplasm that represents the final stage of a continuum of clinical conditions that start from monoclonal gammopathy of unknown significance (MGUS), then transits in the more advance, but still asymptomatic, smoldering MM (SMM), with a final evolution in symptomatic MM. To investigate SMM microenvironment modifications, we studied 16 patients diagnosed at our hospital. Eight of them (group A) developed MM within 2 years from diagnosis while the others (group B) had stable SMM. Samples were bone marrow biopsies at diagnosis and after 2 years (± 4 months) and were analyzed by immunohistochemical analysis. Firstly, we found a significant increase in both CD4+ cells (11 vs 17%, p < 0.01) and CD8+ cells (15 vs 18%, p < 0.01) between diagnosis and at follow-up samples (whole cohort). This was associated to an increase in the CD4+/CD8+ ratio (0.74 vs 0.93, p < 0.01). Secondly, we discovered an increased expression of T cell inhibitory molecules during SMM evolution. In fact, plasma cell PD-L1 and microenvironment cell LAG3 expression increased from 1 to 12% (p = 0.03) and 4 to 10% (p = 0.04), respectively, from diagnosis to follow-up. Also, plasma cells and microenvironment cells HLA-DR expression augmented during SMM evolution from 7 to 10% (p = 0.04) and 29 to 39% (p = 0.01), respectively. When comparing group A vs group B, we found an increased CD68-KP1+ cell infiltration in favor of group B at diagnosis (23 vs 28%, p = 0.01) and a greater plasma cell infiltration at follow-up (50 vs 26%, p < 0.01). Our findings suggest how immune escape mechanisms appear earlier during multiple myeloma evolution, and that LAG3 could be a possible immunologic target in this setting.

RANK expression in EBV positive nasopharyngeal carcinoma metastasis: a ready-to-treat target?

Epstein Barr Virus (EBV) related Nasopharyngeal Carcinoma (NPC), is an highly chemo- and radiosensitive endemic malignancy in southeast Asia. More than one third of locally advanced cases relapse after curative treatment, especially because of bone, liver and lung metastases. Lymphocyte sub-populations favour EBV-associated carcinogenesis and tumour progression and several strategies aim to reverse this phenomenon. Receptor activator of NF-kB (RANK) and its Ligand (RANKL), key regulator of bone metabolisms, are expressed in several malignancies and tumor-infiltrating Tregs. We collected 17 paired FFPE specimen of primary and metachronous metastatic or regionally relapsed EBV related NPC and evaluated RANK expression by immunohistochemistry. All primary tumour specimens resulted not evaluable whereas all metastatic specimens, regardless of sites, showed high RANK IHC expression in the tumor with no staining in normal surrounding tissues. This observation deserves further clarifications and could open the way to trials testing the hypotesis that targeting the RANK/RANKL pathway with denosumab, an already available, clinically approved monoclonal antibody for metastatic bone lesions, might restore proper anti-tumor immune response in NPC metastatic patients.

Loss of succinate dehydrogenase subunit B (SDHB) as a prognostic factor in advanced ileal well-differentiated neuroendocrine tumors.

PURPOSE: Abnormal expression of succinate dehydrogenase, (SDH), in particular of the B subunit (SDHB), is implicated in the pathogenesis of neuroendocrine tumors. This study evaluates the distribution of SDHB in WHO grading G1 and G2 intestinal, well-differentiated neuroendocrine tumors and corresponding lymph node or liver metastases. METHODS: We collected ileal well-differentiated neuroendocrine tumors specimens from consecutive patients with prior primary resection and distant synchronous or metachronous liver metastases. We obtained 195 specimens from primary tumors (n = 106) and metastases (n = 89). The expression (E) of SDHB and the immunostaining intensity (I) were evaluated semiquantitatively and combined into a single score. SDHB score was evaluated in primitive tumor and metastatic specimens. RESULTS: SDHB was found in all tumor cells. Mean SDHB expression was 72.7 % ± 17.1 % in primitive specimens and 27.9 % ± 24.6 % in metastatic specimens (p < 0.0001). SDH intensity was higher in primitive specimens (p < 0.0001). SDHB score was 9-12 in 96 specimens of the primitive group and 2 metastatic specimens (p < 0.0001). None of the analyzed parameters was predictive of overall survival in the primitive subset. In the metastatic subset, loss of SDHB expression, intensity, and score were prognostic factors for survival. Lower expression and intensity of SDHB in metastatic lesions were associated with longer overall survival. When combining SDHB score and Ki-67 % in the metastatic subset, a lower SDHB score was associated with prolonged overall survival, independently from Ki-67 %. CONCLUSIONS: SDHB score was different in primitive and metastatic specimens. The combination of SDHB score and Ki-67 % was a stronger predictor of overall survival than Ki-67 % alone. This stratification might help predict survival.

Mammalian target of rapamycin expression in poorly differentiated endocrine carcinoma: clinical and therapeutic future challenges.

While the mammalian target of rapamycin (mTOR) signaling pathway is a promising target for well-differentiated endocrine carcinoma therapy with the mTOR inhibitor everolimus (RAD001), poorly differentiated endocrine carcinomas (PDECs) are usually excluded from clinical trials due to their aggressiveness. So far, mTOR activity in PDECs has only been tested in cell lines. This study reviewed 36 mono-institutional PDECs to determine mTOR expression. Slides of normal kidney as positive control were used to optimize mTOR staining. To ensure antibody specificity, consecutive sections were incubated in the absence of primary antibody. Immunoreactivity was evaluated on a semi-quantitative scale scoring the extent and intensity of staining. The product of these two scores was used to obtain a total immunostaining score. The main primary site of disease was the pancreas, and 83% of patients had stage IV disease. In 80% of samples, mTOR expression was maintained at similar levels, with no relationship to tumor origin or proliferation rate determined by MIB-1. This study seems to demonstrate that mTOR is expressed in human PDECs regardless of tumor site. Its role in relation to the activity of everolimus in this subset of patients needs to be confirmed.

Combined typical carcinoid and acinic cell tumor of the lung: a heretofore unreported occurrence.

We report a primary combined typical carcinoid and acinic tumor of the lung in a 70-year-old man. Although a similar case was reported previously, to the best of our knowledge this is the first case in which the diagnosis is supported by both immunohistochemical and ultrastructural findings. We review the literature and discuss the implications of this finding.