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Systemic targeted molecular therapy, in the form of a selective BRAF inhibitor with or without a MEK inhibitor, is a standard treatment for patients with BRAF V600 mutation-positive melanoma with unresectable stage III and IV disease. Patients with BRAF mutation-negative primary tumors may manifest BRAF mutation-positive metastatic disease. It is unclear whether all metastatic lesions carry the same BRAF mutation status found in the primary tumor and if discordancy exists, in what frequency it occurs. Primary and matched metastatic lesions in 25 melanoma patients were tested for the BRAF V600E/Ec, V600K, V600D, and V600R mutations using a BRAF RGQ PCR kit (Qiagen). Four patients (16%) had discrepancies between their primary and metastatic melanoma BRAF status. Of these patients, 2 (8%) had BRAF mutation-positive primary melanomas with BRAF mutation-negative metastatic lesions and 2 (8%) patient had BRAF mutation-negative melanoma with a BRAF mutation-positive metastatic lesion. In summary, discordancy of BRAF mutation status is not an infrequent finding between primary and metastatic melanoma. It may be prudent in previously negative patients to determine BRAF mutation status of new metastatic tumors for proper allocation of BRAF inhibitor therapy. Discordant BRAF status may have a role in the varying patterns of response and inevitable resistance seen with BRAF inhibitor therapies.

We evaluated the clinicopathologic and molecular characteristics of mostly incidentally detected, small, papillary renal neoplasms with reverse polarity (PRNRP). The cohort comprised 50 PRNRP from 46 patients, divided into 2 groups. The clinically undetected (<5 mm) neoplasms (n = 34; 68%) had a median size of 1.1 mm (range 0.2–4.3 mm; mean 1.4 mm), and the clinically detected (≥5 mm) neoplasms (n = 16; 32%) which had a median size of 13 mm (range 9–30 mm; mean 16 mm). Neoplasms were positive for GATA3 (n = 47; 100%) and L1CAM (n = 34/38; 89%) and were negative for vimentin (n = 0/44; 0%) and, to a lesser extent, AMACR [(n = 12/46; 26%; weak = 9, weak/moderate = 3)]. KRAS mutations were found in 44% (n = 15/34) of the clinically undetected PRNRP and 88% of the clinically detected PRNRP (n = 14/16). The two clinically detected PRNRP with wild-type KRAS gene were markedly cystic and contained microscopic intracystic tumors. In the clinically undetected PRNRP, the detected KRAS mutations rate was higher in those measuring ≥1 mm vs <1 mm [n = 14/19 (74%) vs n = 1/15 (7%)]. Overall, the KRAS mutations were present in exon 2—codon 12: c.35 G > T (n = 21), c.34 G > T (n = 3), c.35 G > A (n = 2), c.34 G > C (n = 2) resulting in p.Gly12Val, p. Gly12Asp, p.Gly12Cys and p.Gly12Arg, respectively. One PRNRP had a G12A/V/D complex mutation. Twenty-six PRNRP were concurrently present with other tumors of different histologic subtypes in the ipsilateral kidney; molecular testing of 8 of the latter showed wild-type KRAS gene despite the presence of KRAS mutations in 5 concurrent PRNRP. On follow up, no adverse pathologic events were seen (range 1–160 months; mean 44 months). In conclusion, the presence of KRAS mutations in small, clinically undetected PRNRP provides a unique finding to this entity and supports its being an early event in the development of these neoplasms.

Neoplastic cartilage is a common component of teratomas in type II germ cell tumors. Although IDH1/2 mutations have been well-described in somatic cartilaginous tumors, ranging from benign enchondromas to highly aggressive dedifferentiated chondrosarcomas, the presence of IDH1/2 mutations in cartilaginous neoplasms arising from germ cell tumors has not been previously investigated. To better understand the relationship between these tumors and their bone/soft tissue counterpart, we studied the IDH1/2 mutational status of 20 cases of primary mediastinal mixed germ cell tumors with areas of readily identifiable cartilaginous differentiation. Our study found that cartilaginous lesions arising in germ cell tumors have a different frequency and distribution of IDH1/2 mutations compared to those at somatic sites. We identified IDH1/2 mutations in only 15% (3/20) of cases, compared to a frequency in the literature among differentiated chondroid tumors of bone and soft tissue of 54%, a highly significant decreased frequency (p = 0.0011; chi-square test). Furthermore, they were exclusively IDH2 R172 mutations that occurred at a non-significant, increased frequency in the germ cell tumor group compared to conventional chondrosarcoma (15% vs. 5%, respectively, p > 0.05, chi-square test). The unexpected finding, therefore, was entirely attributable to the absence of IDH1 R132 mutation in chondroid neoplasia of germ cell origin (p < 0.00001, Fisher exact test). Our results suggest that a subset of cartilaginous lesions arising within type II germ cell tumors have a similar oncogenic mechanism to their bone/soft tissue counterpart but that the majority form using different oncogenic mechanisms compared to their somatic counterparts.

- In some instances the standard method of doing molecular testing from formalin-fixed, paraffin-embedded block is not possible because of limited tissue. Tumor cell-enriched cell-transfer technique has been proven useful for performing immunocytochemistry and molecular testing on cytologic smears. - To establish the cell-transfer technique as a viable option for isolating tumor cells from hematoxylin-eosin (H&E)-stained slides. - Molecular testing was performed by using the cell-transfer technique on 97 archived H&E-stained slides from a variety of different tumors. Results were compared to the conventional method of molecular testing. - Polymerase chain reaction-based molecular testing via the cell-transfer technique was successfully performed on 82 of 97 samples (85%). This included 39 of 47 cases for EGFR, 10 of 11 cases for BRAF, and 33 of 39 cases for KRAS mutations. Eighty-one of 82 cell-transfer technique samples (99%) showed agreement with previous standard method results, including 4 mutations and 35 wild-type alleles for EGFR, 4 mutations and 6 wild-type alleles for BRAF, and 11 mutations and 21 wild-type alleles for KRAS. There was only 1 discrepancy: a cell-transfer technique with a false-negative >KRAS result (wild type versus G12C). - Molecular testing performed on H&E-stained sections via cell-transfer technique is useful when tissue from cell blocks and small surgical biopsy samples is exhausted and the only available material for testing is on H&E-stained slides.

Cell-transfer technique has been proven useful for performing immunocytochemistry on fine-needle aspiration smears. However, its utility for EGFR and KRAS molecular testing has not been validated. Molecular testing was performed using the cell-transfer technique on both Papanicolaou-stained ethanol-fixed and Hema 3-stained air-dried smears from 32 fine-needle aspiration samples that had diagnoses of adenocarcinoma of the lung, and then was compared to the results of the corresponding formalin-fixed paraffin-embedded tissues. The molecular testing was successfully performed on 32 of 32 ethanol-fixed and 31 of 32 air-dried samples. The molecular results on ethanol-fixed and air-dried smears showed 100% agreement. There is 100% (32/32) agreement for the EGFR and 97% (31/32) agreement for the KRAS between the cell-transfer technique and formalin-fixed paraffin-embedded tissues. One discrepant case was due to low percentage of tumor cells on the smears. Cell-transfer technique is a reliable alternative method for EGFR and KRAS testing if the cell blocks lack adequate cellularity.

The identification of mutations in epidermal growth factor receptor (EGFR) and translocations involving anaplastic lymphoma kinase (ALK) in lung adenocarcinoma has drastically changed understanding of the disease and led to the development of targeted therapies. Adenocarcinoma of the urinary bladder is rare and poorly understood at the molecular level. We undertook this study to determine whether EGFR mutations, increases in EGFR copy number, or ALK translocations are present in these tumors. Twenty-eight cases of primary bladder adenocarcinoma were analyzed. For EGFR mutational analysis, PCR-amplified products were analyzed on the Q24 Pyrosequencer with Qiagen EGFR Pyro Kits. All cases were analyzed via fluorescence in situ hybridization (FISH) using Vysis ALK Break Apart FISH Probes for detection of ALK chromosomal translocation and Vysis Dual Color Probes to assess for increased gene copy number of EGFR. None of the 28 cases examined showed mutational events in EGFR or ALK rearrangements. EGFR polysomy was seen in 10 out of 28 (36%) cases. No correlation with EGFR polysomy was seen in the tumors with respect to age, histologic subtypes, pathologic stage, or lymph node metastasis. In summary, EGFR mutations and ALK rearrangements do not appear to be involved in the development of primary adenocarcinoma of the urinary bladder. A subgroup of cases (36%), however, demonstrated increased gene copy number of EGFR by FISH.

(doi: 10.5858/arpa.2015-0454-OA)