Summary. We evaluated microvessel density (MVD) in bone marrow biopsies (BM) from multiple myeloma (MM) patients after staining with anti-CD34 and anti-CD105 antibodies (mAbs). The anti-CD105 mAb was significantly more sensitive than the anti-CD34 mAb in visualizing blood vessels both in controls and MM samples. MVD was significantly higher in MM than in controls with both anti-CD34 and anti-CD105 mAbs. Patients with low CD34 + MVD survived longer than patients with higher MVD (P = 0AE01), whereas there was no difference in survival between patients with low and high CD105 + MVD. Multivariate analysis confirmed the independent significant association between CD34 + MVD and survival (P = 0AE001).

Meningothelioid nodules (MNs) are not uncommon lesions of the pulmonary interstitium composed of monomorphic round to spindle cells, likely reactive in nature. Their origin is unsettled, though a derivation from arachnoid-like cells in conditions of perturbed perfusion of the pulmonary tissue has been proposed. Here we confirm the consistent occurrence of intense progesterone-receptor immunoreactivity in MNs fortuitously detected in surgical specimens of lung carcinomas. This finding corroborates the view that these proliferations exhibit arachnoid cell-like differentiation and suggests a role for sex-steroid hormones in the control of their growth.

The purpose of this study is to evaluate whether activating mutations of the p110α catalytic subunit of class A phosphoinositide 3-kinases (PI3KCA) or complete loss of phosphatase and tensin homolog (PTEN) is associated with response to anti-human epidermal growth factor receptor 2 (Her2) treatment in breast cancer (BC). We analysed PI3KCA hot-spot mutations and PTEN immunohistochemical expression in 129 Her2-positive infiltrating BC treated with trastuzumab, including 26 cases treated with neoadjuvant therapy, 48 metastatic infiltrating breast cancer (IBC; MBC) and 55 early-stage IBC, with complete clinical information (mean follow-up 37, 66 and 32 months, respectively). PI3KCA hot-spot mutations were observed in 25 cases (19 %): 12 (9 %) in exon 9 and 13 (10 %) in exon 20. No correlations were observed between mutations and pathological and biological parameters. In patients treated with neoadjuvant therapy and in MBC, we did not observe any relationship with response to trastuzumab-based therapy. PTEN loss was observed in 24 out of 86 informative cases (28 %), 3 (13 %) of which were also mutated for PI3KCA. PI3K pathway activation, defined as PI3KCA mutation and/or PTEN loss, was not associated with response to treatment or clinical outcome in MBC. PI3KCA mutation and/or PTEN loss should not exclude patients from potentially beneficial anti-Her2 therapy.