Early lymph node involvement by mantle cell lymphoma limited to the germinal center: report of a case with a novel "follicular in situ" growth pattern.

Recently, several reports have described cases of "in situ" mantle cell lymphoma (MCL) in which scattered cyclin D1+ cells were present within the mantle zones of reactive-appearing lymphoid follicles. In this report, we describe an unusual histologic pattern of in situ MCL that was identified in a staging lymph node for colonic adenocarcinoma resected 4 years before a diagnosis of symptomatic MCL. Retrospective immunohistochemical studies showed scattered cyclin D1-expressing cells within otherwise reactive germinal centers but not in the surrounding mantle zones.

Flow cytometric evaluation of CD38 expression assists in distinguishing follicular hyperplasia from follicular lymphoma.

The distinction of follicular lymphoma (FL) from reactive follicular hyperplasia (FH) can be a diagnostic challenge in flow cytometry. In this study, the median fluorescent intensity (MFI) of CD38 as assessed by flow cytometry on B and T cell subpopulations in 102 lymph nodes specimens with histopathologically confirmed FL was compared with 55 cases of FH. The MFI of CD38 was highly significantly reduced in the neoplastic B cells in FL when compared with the reactive germinal center B cells in FH (P < 1.

Histologically normal human mammary epithelia with silenced p16(INK4a) overexpress COX-2, promoting a premalignant program.

Breast tissue from healthy women contains variant mammary epithelial cells (vHMEC) exhibiting p16INK4a promoter hypermethylation both in vivo and in vitro. When continuously cultured, vHMEC acquire telomeric dysfunction and produce the types of chromosomal abnormalities seen in premalignant lesions of cancer. We find that late passage vHMEC express elevated prostaglandin cyclo-oxygenase 2 (COX-2), which contributes to increased prostaglandin synthesis, angiogenic activity, and invasive ability.

Cyclooxygenase-2 expression is related to nuclear grade in ductal carcinoma in situ and is increased in its normal adjacent epithelium.

Cyclooxygenase-2 (COX-2) is emerging as an important cancer biomarker and is now an experimental target for solid tumor treatment.However, no study has exclusively focused on COX-2 expression in early lesions such as ductal carcinoma in situ (DCIS). We examined COX-2 expression by immunohistochemistry in 46 cases of women undergoing surgical resection for DCIS.