Germ cell tumours (GCTs) are a heterogeneous group of neoplasms, which develop in the gonads as well as in extragonadal sites, that share morphological patterns and an overall good prognosis, owing to their responsiveness to current surgical, chemotherapeutic, and radiotherapeutic measures. GCTs demonstrate extremely interesting biological features because of their close relationships with normal embryonal development as demonstrated by the pluripotentiality of some undifferentiated GCT variants. The similarities between GCTs and normal germ cell development have made it possible to identify possible pathogenetic pathways in neoplastic transformation and progression of GCTs. Genotypic and immunophenotypic profiles of these tumours are also useful in establishing and narrowing the differential diagnosis in cases of suspected GCTs. Recently, OCT4 (also known as OCT3 or POU5F1), a transcription factor that has been recognized as fundamental in the maintenance of pluripotency in embryonic stem cells and primordial germ cells, has been proposed as a useful marker for GCTs that exhibit features of pluripotentiality, specifically seminoma/dysgerminoma/germinoma and embryonal carcinoma. The development of commercially available OCT4‐specific antibodies suitable for immunohistochemistry on paraffin‐embedded specimens has generated increasing numbers of reports of OCT4 expression in a wide variety of gonadal and extragonadal GCTs. OCT4 immunostaining has been shown to be a sensitive and specific marker for seminomatous/(dys)germinomatous tumours and in embryonal carcinoma variants of non‐seminomatous GCTs, whether in primary gonadal or extragonadal sites or in metastatic lesions. Therefore, OCT4 immunohistochemistry is an additional helpful marker both in the differential diagnosis of specific histological subtypes of GCTs and in establishing a germ cell origin for some metastatic tumours of uncertain primary. OCT4 expression has also been reported in pre‐invasive conditions such as intratubular germ cell neoplasia, unclassified (IGCNU) and the germ cell component of gonadoblastoma. Additionally, OCT4 immunostaining shows promise as a useful tool in managing patients known to be at high risk for the development of invasive GCTs. Copyright © 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

To provide further information on the clinical and pathological prognostic factors in triple-negative breast cancer (TNBC), for which limited and inconsistent data are available. Pathological characteristics and clinical records of 841 TNBCs diagnosed between 1994 and 2015 in four major oncologic centers from Sardinia, Italy, were reviewed. Multivariate hazard ratios (HRs) for mortality and recurrence according to various clinicopathological factors were estimated using Cox proportional hazards models. After a mean follow-up of 4.3 years, 275 (33.3%) TNBC patients had a progression of the disease and 170 (20.2%) died. After allowance for study center, age at diagnosis, and various clinicopathological factors, all components of the TNM staging system were identified as significant independent prognostic factors for TNBC mortality. The HRs were 3.13, 9.65, and 29.0, for stage II, III and IV, respectively, vs stage I. Necrosis and Ki-67 > 16% were also associated with increased mortality (HR: 1.61 and 1.99, respectively). Patients with tumor histotypes other than ductal invasive/lobular carcinomas had a more favorable prognosis (HR: 0.40 vs ductal invasive carcinoma). No significant associations with mortality were found for histologic grade, tumor infiltrating lymphocytes, and lymphovascular invasion. Among lymph node positive TNBCs, lymph node ratio appeared to be a stronger predictor of mortality than pathological lymph nodes stage (HR: 0.80 for pN3 vs pN1, and 3.05 for >0.65 vs <0.21 lymph node ratio), respectively. Consistent results were observed for cancer recurrence, except for Ki-67 and necrosis that were not found to be significant predictors for recurrence. This uniquely large study of TNBC patients provides further evidence that, besides tumor stage at diagnosis, lymph node ratio among lymph node positive tumors is an additional relevant predictor of survival and tumor recurrence, while Ki-67 seems to be predictive of mortality, but not of recurrence.