Amarpreet Bhalla

Molecular Diagnostics in Colorectal Carcinoma

Molecular pathogenesis and classification of colorectal carcinoma are based on the adenoma-carcinoma sequence in the Vogelstein model, serrated polyp pathway, and microsatellite instability. The genetic basis for hereditary nonpolyposis colorectal cancer is based on detection of genetic mutations. Genetic testing for Lynch syndrome includes microsatellite instability, methylator phenotyping, BRAF mutation, and molecular testing. Molecular makers include quantitative multigene reverse transcriptase-polymerase chain reaction assay and KRAS and BRAF mutation analysis. Potential biomarkers include one-step nucleic acid amplification and epigenetic inactivation of endothelin 2 and endothelin 3 in colon cancer. Molecular screening approaches in colorectal cancer using stool DNA are under investigation.

Molecular Diagnostics in Esophageal and Gastric Neoplasms

Esophageal carcinoma is the most rapidly increasing tumor in incidence in the United States. It has an established association with a precursor lesion (Barrett esophagus). Gastric carcinoma (GC) is the second leading cause of cancer death in the world. The prognosis for patients with advanced stage GC and esophageal carcinoma is poor. Human epidermal growth factor 2 (HER-2) overexpression is seen in gastroesophageal junction carcinoma and a subset of GC. HER-2 overexpressing tumors are eligible for HER-2 targeted therapies, which lead to a better survival in these patients.

Cytokeratin 5/6 expression in benign and malignant breast lesions.

BACKGROUNDnCytokeratin s (CK) are used for the fingerprinting of carcinomas in general. In breast tissue, the luminal epithelial cells express CK 8/18, CK 7 and CK 19, while basal/myoepithelial cells express CK 5/6, CK 14 and CK 17.nnnMATERIAL AND METHODSnImmunohistochemical staining for cytokeratin 5/6 was applied on cell block sections of 23 cases of benign and 25 cases of malignant breast lesions using avidin biotin peroxidase technique. The distribution and intensity of staining was recorded and graded semiquantitatively.nnnRESULTnAll benign lesions showed positive immunoreaction, with the staining index varying from 6-9, except lactating adenoma. The malignant lesions comprised three cases of ductal carcinoma in situ (DCIS) and 22 cases of infiltrating ductal carcinoma, not otherwise specified, IDC (NOS). None of the DCIS cases showed a positive immunoreaction. Among the IDC (NOS) lesions, six cases of grade III breast carcinoma exhibited a positive immunohistochemical reaction, the staining index of which varied from 2-6. The staining reaction in the malignant lesions was only cytoplasmic and the intensity was significantly less than that of benign lesions.nnnCONCLUSIONnCK 5/6 expression breast carcinoma implies a basal like molecular phenotype and is associated with poor prognosis. This antibody is also used as a component of panels to differentiate benign and malignant breast lesions.

Histopathological evidence of neoplastic progression of von Meyenburg complex to intrahepatic cholangiocarcinoma

Von Meyenburg complex (VMC) is generally thought to be benign, although its preneoplastic potential for intrahepatic cholangiocarcinoma (iCC) has been a subject of contention. We retrospectively reviewed 86 hepatectomy specimens with a diagnosis of iCC. Morphologically, an association between iCC and VMC was appreciated in 35% of cases that illustrated a gradual neoplastic progression from benign VMC to dysplasia and then to iCC. Among them, 24 cases had VMC lined by epithelial cells with low-grade biliary dysplasia and 13 with high-grade biliary dysplasia. VMC-associated iCCs were smaller in size and well to moderately differentiated, with features of anastomosing glandular architecture, ductal carcinoma in situ-like growth pattern, peritumoral lymphocytic infiltrate, central fibrous scar, and complete pushing border. They often presented as T1 tumors. In contrast, non-VMC-associated iCCs were moderately to poorly differentiated with solid, cribriform or papillary growth patterns. They likely exhibited necrosis, perineural invasion, positive surgical margin, lymphovascular invasion, and high T stage. Additionally, Ki67 and p53 immunostains support the continuing neoplastic evolution from benign VMC to dysplasia and then to iCC. VMC could become neoplastic, serving as an in situ carcinoma lesion to transform to iCC. The underlying molecular alteration and clinical implication of this neoplastic transformation deserves further investigation.

Etiologic factors related to unsatisfactory ThinPrep® cervical cytology: Evaluation and potential solutions to improve

Background: In cervical cytology, the unsatisfactory rates for ThinPrep (TP) are slightly higher compared to SurePath. We examined various causes and explored potential for resolution of this discrepancy. Materials and Methods: Totally, 19,422 cases were reviewed and 1000 unsatisfactory specimens were selected and analyzed. 531 specimens were available for wash protocol. Out of 114 unsatisfactory specimens associated with atrophic cellular changes (ACC), 48 were resubmitted by provider and reevaluated. Results: Lubricant and lubricant-like debris/contamination (LUBE) was the most common cause of unsatisfactory specimens (68%; 681/1000) followed by blood (7.5%); ACC only (without other interfering factors) (2.4%); inflammation (3.0%); and combinations thereof (1.9%). 11.5% showed scant cellularity without an identifiable cause. 3.3% were virtually acellular. Wash protocol improved cellularity in 48% (256/531) of cases. However, only 29% (73/256) of those were satisfactory (with more than 5000 cells). Quantitative reduction in LUBE after wash protocol varied with different morphological subtypes. Interpretation patterns on satisfactory specimens after wash protocol were comparable to the results on selected cohort of specimens during the same study period. Out of 114 ACC, wash protocol was performed on 68 ACC specimens leading to satisfactory TP in 24% (16/68). Totally, 48 cases reported as unsatisfactory with ACC, were resubmitted by the providers between 2 weeks and 2 years. 44 (92%) showed increased cellularity, out of which 52% (23/44) did not show ACC. Conclusion: LUBE was the most common cause of unsatisfactory TP in addition to interference by blood and association with atrophic changes. Knowing the morphological spectrum of LUBE would help to identify it as the cause of unsatisfactory TP. Communicating the cause of unsatisfactory TP such as LUBE, ACC, and blood would hint the provider to take appropriate precaution during submission of the repeat specimen, leading to improved patient care.

Molecular Diagnostics in the Neoplasms of the Pancreas, Liver, Gall Bladder, and Extrahepatic Biliary Tract

Pancreatic neoplasms, including ductal adenocarcinoma, intraductal papillary mucinous neoplasm, solid pseudopapillary neoplasm, pancreatic endocrine neoplasms, acinar cell carcinoma, and ampullary carcinoma, are associated with different genetic abnormalities. Liver neoplasms, including hepatic adenomas, hepatocellular carcinomas, and cholangiocarcinomas, are associated with identifiable risk factors and genetic changes. Gall bladder adenomas and adenocarcinomas arise from distinct molecular pathways. The molecular abnormalities seen in these tumors are not used routinely in the molecular diagnostic laboratory.

Mucinous intrahepatic cholangiocarcinoma: a distinct variant

Mucinous variant of intrahepatic cholangiocarcinoma (iCC) is rare, and its clinicopathological features and prognosis are far less clear. Six patients who had iCCs with more than 50% of mucinous component and 79 conventional iCCs were included in the study. The mean size of mucinous and conventional iCCs was 6.2 and 6.0u202fcm, respectively. Most patients (83%) with mucinous iCC presented at T3 stage or above compared with 28% of the conventional group (Pu202f<u202f.01). Three patients with mucinous iCC (50%) died within 1u202fyear. The average survival time of patients with mucinous iCCs was significantly reduced compared with that of the conventional group (9u202fmonths versus 2u202fyears; Pu202f<u202f.001). Immunohistochemistry was performed on 6 mucinous and 12 conventional iCCs with matched age, sex, and stage, which revealed positive immunoreactivity in MUC1 (83% versus 58%), MUC2 (33% versus 17%), MUC5AC (100% versus 42%), MUC6 (50% versus 0), CK7 (83% versus 83%), CK20 (0 versus 17%), CDX2 (17% versus 0), p53 (67% versus 67%), Smad4 (67% versus 58%), and EGFR (83% versus 42%) in mucinous and conventional iCCs, respectively. Molecular studies showed one mucinous iCC with KRAS G12C mutation and no BRAF or IDH1/2 mutations. Mucinous iCC is a unique variant that constitutes 7% of iCCs. It is more immunoreactive for MUC1, MUC2, MUC5AC, and MUC6. Unlike adenocarcinomas of colorectal primary, mucinous iCCs are often CK7+/CK20-/CDX2- and microsatellite stable. Patients with mucinous iCC likely present at advanced stage upon diagnosis with shorter survival time compared with the conventional counterparts.

Molecular Diagnostics in Colorectal Carcinoma: Advances and Applications for 2018.

The molecular pathogenesis and classification of colorectal carcinoma are based on the traditional adenomaecarcinoma sequence, serrated polyp pathway, and microsatellite instability (MSI). The genetic basis for hereditary nonpolyposis colorectal cancer is the detection of mutations in the MLH1, MSH2, MSH6, PMS2, and EPCAM genes. Genetic testing for Lynch syndrome includes MSI testing, methylator phenotype testing, BRAF mutation testing, and molecular testing for germline mutations in MMR genes. Molecular makers with predictive and prognostic implications include quantitative multigene reverse transcriptase polymerase chain reaction assay and KRAS and BRAF mutation analysis. Mismatch repair-deficient tumors have higher rates of programmed death-ligand 1 expression. Cell-free DNA analysis in fluids are proving beneficial for diagnosis and prognosis in these disease states towards effective patient management.

Molecular Diagnostics in Esophageal and Gastric Neoplasms: 2018 Update

Esophageal cancer (EC) is rapidly increasing in incidence in the United States. Genetic changes associated with the development of EC involve the p16, p53, and APC genes. Human epidermal growth factor 2 (HER-2) overexpression is seen in gastroesophageal junction carcinoma and a subset gastric carcinoma (GC). Interestingly, up to 50% cases of GC are related to Helicobacter pylori infection and up to 16% are related to EBV infection. Microsatellite instability is observed in up to 39% of GC and cell free nucleic acid analysis provides additional opportunities for diagnosis and prognosis of disease.

Thyroid gland and adjacent lesions: Cytomorphological clues!

A 65-year-old female presented for evaluation of hypertension. Physical examination revealed a painless lump in the neck. Ultrasound examination of the thyroid showed a posteriorly located, hypervascular, single hypoechoic, solid lesion, measuring 1.4 cm, near the upper pole of the left thyroid gland. Figure u200bFigure1a1a–d shows the cytomorphological features of the fine needle aspirate in Diff-Quik stained smears. Papanicolaou (Pap) stained smears were suboptimal with scant cellularity. n n n nFigure 1 n nFine-needle aspiration of neck lesion (Diff-Quik stained preparation). (a) Mildly cellular smear without colloid (×4). (b) Showing small groups of cells forming syncitia, admixed with a few bare nuclei (arrowheads). Inset of “b” ...